The cities of San Francisco, Berkeley, Fremont and Watsonville and Contra Costa, Monterey, Santa Clara and Sonoma counties on Wednesday were among 29 jurisdictions nationwide to receive sanctuary warning letters from the U.S. Department of Justice.
The letters say the department is concerned that the cities' and counties' policies may violate a federal law that bars local governments from preventing their employees from communicating with federal immigration agents.
Compliance with the law, known as Section 1373, is a condition of Justice Department grants to local governments under a program known as the Edward Byrne Memorial Justice Assistance Program.
The letters signed by Acting Assistant Attorney General Alan Hanson ask the cities and counties to submit a response by Dec. 8 explaining whether they have "laws, policies or practices" that violate the law.
The letters also ask the recipients to state whether they would comply with the law if they receive a Byrne grant in the current fiscal year, which began on Oct. 1.
"Jurisdictions that adopt so-called 'sanctuary policies' also adopt the view that the protection of criminal aliens is more important than the protection of law-abiding citizens and of the rule of law," Attorney General Jeff Sessions said in a statement.
He continued: "I urge all jurisdictions found to be potentially out of compliance in this preliminary review to reconsider their policies that undermine the safety of their residents."
San Francisco City Attorney Dennis Herrera strongly disagreed with the Justice Department's analysis.
"San Francisco is in full compliance with federal immigration law," he said in a statement.
Herrera said the administration of President Donald Trump is making "novel and shifting interpretations" of the Section 1373 law, "going far beyond its text."
"The law means what it says, and we follow it," he said.
Herrera said San Francisco restricts other cooperation with immigration officials, but maintained that such local restrictions don't violate federal laws.
"This letter is the latest salvo in the barrage of Trump administration threats to sanctuary cities," he said. "The law is on our side, and we intend to beat back this threat, just like all the others before it."
In the South Bay, Santa Clara County said there is one problem with the threat.
"The big joke on them is we never took any money from them in 2016," Santa Clara County Supervisor Dave Cortese said.
NBC Bay Area's Damian Trujillo contributed to this report.