This has been CNBC's live blog covering updates on the war in Ukraine. Follow the latest updates here.

U.S. first lady Jill Biden paid a surprise visit to Ukraine and held a Mother's Day meeting with her Ukrainian counterpart, Olena Zelenskyy.

Biden's visit comes after recent trips to the country by House Speaker Nancy Pelosi, as well as U.S. Secretary of State Antony Blinken and Defense Secretary Lloyd Austin.

Her visit also comes as dozens are feared dead after reports that a school in the Luhansk region in eastern Ukraine has been hit by Russian shelling. Luhansk is one of the two regions that make up the Donbas, where Russian troops are now concentrating their efforts.

Meanwhile, the last women, children and elderly people have been evacuated from the Azovstal steel plant, the final holdout for Ukrainians in the besieged port city of Mariupol, according to Ukraine's deputy prime minister.

Ukraine's famous mine sniffing dog Patron awarded medal by Zelenskyy

President Volodymyr Zelenskyy presented Ukraine's famous mine sniffing dog Patron and his owner with a medal to recognize their dedicated service since Russia's invasion.

The pint-size Jack Russell terrier has been credited with detecting more than 200 explosives and preventing their detonation since the start of the war on Feb. 24, quickly becoming a canine symbol of Ukrainian patriotism.

Zelenskyy made the award at a news conference in Kyiv with Canadian Prime Minister Justin Trudeau. Patron barked and wagged his tail, prompting laughter from the audience. Trudeau patted his pockets as though looking for a dog treat.

"Today, I want to award those Ukrainian heroes who are already clearing our land of mines. And together with our heroes, a wonderful little sapper - Patron - who helps not only to neutralize explosives, but also to teach our children the necessary safety rules in areas where there is a mine threat," Zelenskyy said in a statement after the ceremony.

The award also went to Patron's owner, a major in the Civil Protection Service, Myhailo Iliev.

— Reuters

Japan to ban Russian oil imports 'in principle,' Prime Minister Kishida says

Japan will ban Russian crude oil imports "in principle," as part of a Group of Seven countries campaign to counter Russia's invasion of Ukraine, Prime Minister Fumio Kishida said after an online meeting of G-7 leaders.

"For a country heavily dependent on energy imports, it's a very difficult decision. But G-7 coordination is most important at a time like now," Kishida said, according to a statement released by the government.

— Reuters

Britain to boost tariffs on Russian platinum, palladium in new round of sanctions

Britain will increase tariffs on platinum and palladium imports from Russia and Belarus in a new package of sanctions targeting 1.7 billion pounds ($2.10 billion) of trade, which it said aimed to further weaken Russian President Vladimir Putin's war machine.

Import tariffs on a range of products will be raised by 35 percentage points, Britain said, while it will also ban exports of goods such as chemicals, plastics, rubber and machinery to Russia, worth a combined 250 million pounds ($310 million).

The UK government will legislate for the new sanctions in due course, it said.

British Finance Minister Rishi Sunak said more than 4 billion pounds of goods would be subject to import and export sanctions, doing "significant damage to Putin's war effort." They mark a third wave of sanctions against Russia since the invasion of Ukraine.

"Working closely with our allies we can and will thwart Putin's ambitions," Sunak said in a statement.

— Reuters

More than 170 evacuees from Mariupol arrive in Zaporizhzhia, humanitarian groups say

More than 170 Ukrainian civilians who were evacuated from the Azovstal steel plant and other areas around the besieged port city of Mariupol have arrived in Ukraine-controlled Zaporizhzhia, in the southeastern part of the country.

The latest group of evacuees, who were sheltered in place through more than 10 weeks of shelling and fighting, brings the total number of people evacuated from the area to more than 600, according to the United Nations' Resident Coordinator's Office in Ukraine. 

The United Nations and the International Committee of the Red Cross have been carrying out the evacuations.

"This is the 3rd safe passage operation we've coordinated with @UN," the ICRC wrote in a tweet. "We're deeply relieved we could help more civilians get to a safer place."

— Sarah O'Brien

U.S., G-7 will 'step up' short-term financial support

The U.S. and the Group of Seven will increase its short-term financial support for Ukraine in the coming weeks, G-7 leaders said in a statement.

"We will step up our collective short-term financial support to help Ukraine close financing gaps and deliver basic services to its people, while also developing options – working with the Ukrainian authorities and international financial institutions – to support long-term recovery and reconstruction," according to the release.

President Joe Biden and leaders of the G-7, which consists of the United States, Britain, France, Germany, Japan, Canada and Italy, met virtually with Ukrainian President Volodymyr Zelenskyy earlier in the day.

During the meeting, Zelenskyy stressed the importance for Ukraine "to protect its sovereignty and territorial integrity."

"In this regard, Ukraine emphasized that it relies on its international partners, in particular on G-7 members, in providing necessary assistance in the domain of defense capabilities, as well as with a view to ensuring a swift and effective recovery of Ukraine's economy and to securing its economic and energy security," the release said.

— Jessica Bursztynsky

U.S. diplomats arrive in Kyiv ahead of plans to reopen embassy

The top American diplomat to Ukraine has returned to Kyiv ahead of fully resuming operations at the U.S. Embassy there.

"Just arrived in Kyiv! Delighted to be back on Victory in Europe Day," the embassy said in a tweet, along with a photo of Charge d'Affaires Kristina Kvien.

The Biden administration closed the U.S. embassy in Ukraine on Feb. 14, days before Russia invaded Ukraine.

While it's uncertain exactly when the embassy will fully reopen, doing so was a pledge made to Ukrainian President Volodymyr Zelenskyy by U.S. Secretary of State Antony Blinken during his most recent trip there, U.S. officials said.

— Sarah O'Brien

Moscow focusing on destroying airfield infrastructure, Ukraine says

The Ukrainian army said that Moscow is focusing its main efforts on destroying airfield infrastructure in eastern and southern Ukraine, in order to prevent Ukrainian air forces from operating effectively.

At least five explosions were heard in the key Ukrainian Black Sea port of Odesa on Sunday, according to reports in local news media. Odesa, Ukraine's third-largest city and a cultural center of deep significance to both Ukrainians and Russians, has so far been largely spared in the 10-week-old war.

Multiple photos and videos appeared to show trails and clouds of smoke in the sky above the city. Local media also reported that at least one missile had been shot down. As of Sunday afternoon, there have been no reports of casualties, although one newspaper claimed that civilian infrastructure had been damaged.

According to a Facebook post on the profile of Ukraine's General Chiefs of Staff, Russia also ramped up "operational and tactical aviation activity" in the northwestern part of the Black Sea.

The Kharkiv regional administration says three people were killed in shelling of the town of Bogodukhiv, about 50 kilometers (31 miles) from the northeastern city of Kharkiv.

— The Associated Press

Artifacts of war on display in Kyiv ahead of 'Victory Day' celebrations

Artifacts of war are seen outside the National Museum of Military History of Ukraine in Kyiv. The exhibit's curator Pavlo Netesov hopes the freshly destroyed equipment will serve as a visible reminder of the war's toll to residents in downtown Kyiv -- who have been largely spared from the harsh ground fighting that has erupted elsewhere across the country. 

— Getty Images

U.S., G-7 announce slew of new sanctions against Russia

The Group of Seven is committing to phasing out or banning the import of Russian oil, a senior administration official said on a call with reporters.

The move by the G-7 countries —which consists of the United States, Britain, France, Germany, Japan, Canada and Italy — is meant to hard-hit the Russian economy and deny leader Vladimir Putin of revenue to fund the war, the official said.

The European Union, which has so far struggled to push through an oil ban, is also on the cusp of cutting off that trade, the official said.

The actions come as part of a slew of initiatives from the United States, European Union and G-7 ahead of Russia's planned "Victory Day" celebrations. President Joe Biden and fellow G-7 leaders also virtually met with Ukrainian President Volodymyr Zelenskyy on Sunday.

The U.S. official said that they believe some Russian companies have asked American firms for advice on how to reformulate their business strategies in the wake of U.S. sanctions. With that, Washington will prohibit Americans from providing accounting, trust and corporate formation, and management consulting services to any person in the Russian Federation.

The U.S. is also issuing a new rule that imposes additional restrictions on Russia's industrial sector, including a broad range of inputs and products including wood products, industrial engines and several other items with industrial and commercial applications. It comes in an effort to limit Russia's access to items and revenue that could support its military capabilities.

There's also been a strong focus on Russian elites and their family members.

American officials imposed about 2,600 visa restrictions on Russian and Belarusian officials in their response to the war. The U.S. has also issued a new visa restriction policy that applies to Russian Federation military officials or Russia-backed or Russia-installed purported authorities who are believed to be involved in human rights abuses, violations of international humanitarian law or public corruption in Ukraine.

The U.S. additionally is announcing sanctions on three television stations: Joint Stock Company Channel One Russia, Television Station Russia-1, and Joint Stock Company NTV Broadcasting Company. All three of the stations, which are directly or indirectly controlled by the Russian state, have been among the largest recipients of foreign revenue, which the U.S. said feeds back to the Kremlin.

— Jessica Bursztynsky

Lockheed Martin looks to nearly double Javelin missile production

Weapons maker Lockheed Martin plans to nearly double production of Javelin missiles, the antitank weapon that has helped Ukraine fight Russia's invasion, CEO James Taiclet said in an interview on Sunday.

The aim is to boost output to 4,000 per year from 2,100 per year currently, Taiclet said in an interview with CBS News. The increase will take as long as a couple of years, he said.

U.S. President Joe Biden last week visited a Lockheed facility in Alabama that manufactures the weapons, which are made jointly by Lockheed and Raytheon Technologies, in an effort to press Congress to approve his proposed $33 billion assistance package for Ukraine.

The United States has rushed $3.4 billion worth of weapons to Ukraine since Russia invaded on Feb. 24, including Javelins as well as howitzers, anti-aircraft Stinger systems, ammunition and body armor.

— Reuters

Zelenskyy, German parliament president discuss arms, Ukraine's EU membership bid

The president of the German parliament Baerbel Bas met Ukrainian President Volodymyr Zelenskyy in Kyiv on Sunday to commemorate victims of World War Two, discuss arms and Ukraine's ambition to be considered for European Union (EU) membership.

In a video of a meeting with Bas, Zelenskyy said securing the Bundestag's approval of heavy arms deliveries to help Ukraine fend off Russian attacks was one his country's "top priorities."

He also asked Bas and the Bundestag to support Ukraine in its bid for European Union membership, which Kyiv's allies have said they want soon. However, candidature would have to be agreed unanimously and accession usually takes years of complex negotiations.

Zelenskyy earlier gave an emotional address for Victory Day, when Europe remembers the formal surrender of Germany to the Allies in World War Two, saying that "evil has returned" to Ukraine, but it wouldn't be able to escape responsibility.

— Reuters

Ukraine ambassador to the U.S.: 'We are preparing for everything' ahead of Russia's 'Victory Day'

Ukraine's Ambassador to the U.S. said Sunday that the nation is making preparations ahead of Russia's Victory Day.

"We know that there are no red lines for the regime in Moscow, so we are preparing for everything," Oksana Markarova said Sunday on CBS' "Face the Nation."

"We can count that Putin and imperialistic Russia will do everything bad they can possibly try to do. The question is, are we all prepared — the civilized world — to do everything possible to defend our democracy and freedom," she said.

Monday's "Victory Day" is a key date for Russia. It marks the then-Soviet Union's defeat of Nazi Germany at the end of World War II in 1945.

Russian President Vladimir Putin is expected to make a speech tomorrow, with massive military parades through the center of Moscow also expected.

— Pippa Stevens, Holly Ellyatt

Pelosi says Congress will deliver aid to Ukraine 'as quickly as possible'

House Speaker Nancy Pelosi said Congress must deliver aid to Ukraine "as quickly as possible."

"We have great bipartisanship in terms of our support for the fight for democracy that the people of Ukraine are making," she said Sunday on CBS' "Face the Nation."

"We have a recognition of the need for more weapons, more sanctions, more economic assistance and more humanitarian assistance," she said.

When asked if Congress could pass the aid package by the end of the month, Pelosi responded with: "I think we have to."

"We're very current on the needs and the urgency. And again, we will have bipartisanship as we go forward with it," she said.

President Joe Biden asked Congress for $33 billion to fund both humanitarian and military aid to Ukraine.

"It's not cheap. But caving to aggression is going to be more costly," Biden said on April 28.

The package has since run into hurdles due to a dispute over immigration policy.

— Pippa Stevens

U.S. ambassador to the UN says it's not necessary for U.S. to label Russia a state sponsor of terrorism

Linda Thomas-Greenfield, U.S. ambassador to the United Nations, said it isn't necessary for the Biden administration to designate Russia as a state sponsor of terrorism, arguing that Russia has already "defined their role on that list."

"They are carrying out terror acts against the Ukrainian people," Thomas-Greenfield said during an interview with CNN's "State of the Union."

"It's not necessary for us to put them on," she said. "They certainly deserve to be called out for the acts of terror that they are committing."

The comments come after Ukrainian President Volodymyr Zelenskyy in April asked President Joe Biden to label Russia a state sponsor of terrorism.

U.S. officials have argued that specific sanctions triggered by the state sponsor of terror label, such as arms embargoes and trade restrictions, have all already been imposed on Russia.

To qualify as a state sponsor of terrorism, a country must have "repeatedly provided support for acts of international terrorism," according to the State Department's official definition. Cuba, Iran, North Korea and Syria are currently on the list.

— Emma Newburger

Canadian PM Justin Trudeau visited Irpin, mayor says

Canadian Prime Minister Justin Trudeau made an unannounced visit to Irpin, the city's Mayor said in a Telegram post.

"He came to Irpin to see with his own eyes all the horror that the Russian occupiers had done to our city," Oleksandr Markushin said of Trudeau in the translated post. "Of course, he was shocked. After all, he saw burned and completely destroyed non-military facilities, the homes of Irpin residents, who until recently enjoyed life and had their own plans for the future."

NBC News could not immediately verify the visit.

Irpin, a suburb of Kyiv, suffered massive destruction after Russian troops attempted and failed to overtake the area. Ukrainian officials allege that as they departed, Russian forces executed civilians and committed other heinous war crimes.

—Jessica Bursztynsky

Hungary reportedly remains opposed to EU's Russian oil ban

Hungary is still resisting the European Union's proposal to ban Russian oil imports, according to a report from Bloomberg News.

The bloc's ambassadors met on Sunday but failed to reach an agreement, the report said, citing people familiar with the discussions.

The EU outlined the proposed new sanctions against the Kremlin on Wednesday.

"Some member states are strongly dependent on Russian oil. But we simply have to work on it," European Commission President Ursula von der Leyen said in a speech before the European Parliament on Wednesday.

"We now propose a ban on Russian oil. This will be a complete import ban on all Russian oil, seaborne and pipeline, crude and refined," she added.

In addition to Hungary, Slovakia has also demanded exemptions. Both are highly dependent on Russian energy.

Click here to read the full Bloomberg News story.

— Pippa Stevens

Jill Biden pays surprise visit to Ukraine, meets first lady

U.S. first lady Jill Biden made an unannounced visit to western Ukraine, holding a surprise Mother's Day meeting with the nation's first lady, Olena Zelenskyy, as Russia presses its punishing war in the eastern regions.

Biden traveled under the cloak of secrecy, becoming the latest high-profile American to enter Ukraine during its 10-week-old conflict with Russia.

Her visit follows recent stops in the war-torn country by U.S. House Speaker Nancy Pelosi and other members of Congress, as well as a joint trip by U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin to meet with President Volodymyr Zelenskyy in Kyiv.

The first lady traveled by vehicle to the town of Uzhhorod from a Slovakian village that borders Ukraine.

— The Associated Press

U.S. gas prices rise as Russia's war upends global energy markets

U.S. gas prices marched higher Sunday, as Russia's war on Ukraine wreaks havoc on global energy markets. Sanctioning of Russian energy products and the European Union's proposed plan to move away from dependence on the nation's energy has sent oil and natural gas prices soaring. This, in turn, has boosted the price U.S. consumers are paying at the pump.

Retail diesel prices in the U.S. hit a record $5.53 Sunday, according to AAA. Prices are $2.43 above where they were last year.

The national average for a regular gallon of gasoline stood at $4.317 on Sunday, just shy of March's record $4.33.

— Pippa Stevens

U2's Bono, the Edge perform in Kyiv metro station, tour Bucha

U2's Bono and the Edge performed in a Kyiv metro station after being invited by Ukrainian President Volodymyr Zelenskyy, the band said on Twitter.

The effort was "a show of solidarity with the Ukrainian people," U2 said.

Bono and the Edge also toured Bucha, a city near Kyiv that was briefly under Russian control. When it became clear that the Russian forces could not take the capital, they left. In their wake, Ukrainian officials say they found hundreds of dead civilians, many with indications they were executed, raped or tortured.

—Jessica Bursztynsky

Ukraine troops retreat from Popasna, Luhansk governor confirms

Ukrainian troops retreated from the eastern Ukrainian city of Popasna, the governor of Luhansk region said, confirming previous reports that it had been taken.

The head of Russia's republic of Chechnya, Ramzan Kadyrov, had said on Sunday his troops had taken control of most of Popasna.

Luhansk Governor Serhiy Gaidai told Ukraine television that Ukrainian troops had retreated to take up more fortified positions, adding: "Everything was destroyed there."

Russian forces launched a new offensive push in April along most of Ukraine's eastern flank, with some of the most intense attacks and shelling taking place recently around Popasna in the Luhansk region.

— Reuters

Dozens feared dead after bomb hits school in Luhansk region

Serhiy Haidai, the governor of the Luhansk region, said Sunday that at least two people had died after the bombing of a school.

Haidai said, according to a Reuters translation, that the bombing occurred Saturday afternoon where 90 people had been sheltering. He said 30 had been rescued with around 60 still likely to be under the debris and feared dead.

Luhansk is one of the two regions that make up the Donbas — in the east of Ukraine — where Russian troops are now concentrating their efforts.

The Associated Press added that the school was located in the village of Bilogorivka. Rescue work is ongoing.

NBC News was not able to independently verify the reports.

"The fire was extinguished after nearly four hours, then the rubble was cleared, and, unfortunately, the bodies of two people were found," Haidai wrote on the Telegram messaging app, according to Sky News.

"Thirty people were evacuated from the rubble, seven of whom were injured. Sixty people were likely to have died under the rubble of buildings." 

—Matt Clinch

Russian commanders being exposed to significant risk, UK intelligence says

In a new intelligence update Sunday, the U.K.'s Defence Ministry has reported how senior Russian commanders have been drawn onto the battlefield due to what it describes as a "faltering Russian performance on the front line."

"The forward deployment of commanders has exposed them to significant risk, leading to disproportionately high losses of Russian officers in this conflict. This has resulted in a force that is slow to respond to setbacks and unable to alter its approach on the battlefield," it said in a series of tweets.

—Matt Clinch

Zelenskyy says Russia's actions 'beyond words' after missile destroys museum

Ukrainian President Volodymyr Zelenskyy said that everyday of this war, Russian forces does something that is "beyond words," following a strike against a museum in Ukraine.

"Every day of this war, the Russian army does something that is beyond words. But every next day it does something that makes you feel it in a new way," he said in a regular late-night address on Saturday.

"Targeted missile strikes at museums — this is not even every terrorist can think of," Zelenskyy added.

The museum that was destroyed is dedicated to the 18th century philosopher and poet Hryhoriy Skovoroda.

But this is the kind of army that is fighting Ukraine, and "this is what they want to bring to other European countries," he said.

As of May 7, the Russian army has destroyed or damaged nearly 200 cultural heritage sites, according to Zelenskyy.

— Weizhen Tan

UK to provide about $1.6 billion of further military support to Ukraine

Britain said it would provide a further 1.3 billion pounds (US$1.6 billion) in military support and aid to Ukraine, making the pledge ahead of a planned video call on Sunday by Group of Seven leaders with Ukrainian President Volodymyr Zelenskyy.

Prime MinisteBoris Johnson has been one of the strongest supporters of Ukraine's efforts to resist Russian forces since Russian President Vladimir Putin launched the invasion on Feb. 24. Johnson's government has sent anti-tank missiles, air defense systems and other weapons to Ukraine.

The new pledge almost doubles Britain's previous spending commitments on Ukraine and the government said this is the highest rate of spending on a conflict since the wars in Iraq and Afghanistan, although it did not give details of this calculation.

"Putin's brutal attack is not only causing untold devastation in Ukraine — it is also threatening peace and security across Europe," Johnson said in a statement. Last week he became the first Western leader to address Ukraine's parliament since the start of the invasion.

The leaders of the G-7 countries — Britain, Canada, France, Germany, Italy, Japan and the United States — will hold their virtual meeting with Zelenskyy on Sunday, the day before Russia marks its Victory Day holiday, which marks the end of World War II in Europe.

Britain said the extra spending on Ukraine will come from a reserve used by the government for emergencies.

— Reuters

Zelenskyy says more than 300 people evacuated from Mariupol steel plant

More than 300 civilians have been evacuated from the Azovstal steel plant in Mariupol, according to Ukrainian President Volodymyr Zelenskyy.

"I am grateful to the teams of the International Committee of the Red Cross and the United Nations Organization, who helped us organize the first phase of the evacuation missions from Azovstal," Zelenskyy said in a video posted to Telegram.

Civilians and soldiers have been barricaded at the massive steel plant since mid-April. 

Zelenskyy says preparations are underway for the second phase of the evacuation mission, which includes rescuing the wounded and the doctors.

— MacKenzie Sigalos

Read CNBC’s previous live coverage here:

Zelenskyy says more than 300 civilians rescued from besieged steel plant, more evacuations planned