Former Secretary of State John Kerry said Monday imposing new economic sanctions against Iran could back the country into a corner, and that would be dangerous.
Kerry spoke in San Francisco at a fundraiser for Ploughshares Fund, an organization that works to reduce the threats posed by nuclear weapons.
He said new sanctions on people involved in Iran's ballistic missile program could send a message to the Iranian people that there is no gain for them in the 2015 nuclear deal. The landmark agreement eased economic sanctions in return for a freeze on Iranian nuclear development.
Last month, the Senate's Foreign Relations Committee voted 18-3 in favor of legislation that would authorize President Donald Trump to impose new sanctions on Iran.
Kerry told the gathering Monday that climate change and nuclear weapons are the top threats to the world, and they are threats the current administration must handle carefully.
During his service at secretary of state, he said Iran's ability to make nuclear weapons was an urgent concern.
"Clearly, we were moving toward conflict," Kerry said.
Kerry says he's hopeful Trump would listen to the "good people" he has in his administration.
"My hope is we will not open up a possibility for confrontation when we have so many others to deal with," he said.
In terms of world relations, Kerry said the U.S must continue to be a global power diplomatically and scientifically to help maintain world order.
He said climate change and its impacts are real.
Even after Trump announced his withdrawal from the Paris climate accord, a frustrated Kerry remained optimistic because so many states and citizens are already on board.
"We can build critical mass in this country that is limiting damage, and then in 2018, if you have impact, boom, a different dynamic," Kerry said.
Kerry isn't just talking and taking action. He said he has an upcoming trip to Vietnam, where he is hoping to convince leaders there to scrap plans to build new coal plants and instead build renewable energy resources.