The US government has been accused of "declaring war" on California, after the Justice Department sued to stop policies that protect illegal immigrants against deportation.
California governor Jerry Brown made the charge shortly after Attorney General Jeff Sessions, in a speech in the state capital, intensified the Republican administration's confrontation with California.
Mr Sessions accused California of obstructing federal immigration enforcement efforts and vowed to stop the state's defiance.
Mr Sessions addressed a law enforcement group in Sacramento a day after the Justice Department filed suit against California, Mr Brown and the state's Democratic attorney general over so-called sanctuary policies that shield illegal immigrants.
"California absolutely, it appears to me, is using every power it has - powers it doesn't have - to frustrate federal law enforcement. So you can be sure I'm going to use every power I have to stop them," Mr Sessions, the top US law enforcement officer, said in his speech.
The Democratic governor called the attorney general's trip to California a political stunt and his description of California's laws a lie.
"Like so many in the Trump administration, this attorney general has no regard for the truth," Mr Brown told reporters, adding that the laws were crafted with input and support from California police chiefs. "This is basically going to war against the state of California."
Mr Brown in October signed into law a bill that prevents police from inquiring about immigration status and curtails law enforcement cooperation with immigration officers.
Mr Sessions said US Immigration and Customs Enforcement (ICE) agents carry out federal law and that "California cannot forbid them or obstruct them in doing their jobs".
"In recent years, the California legislature has enacted a number of laws designed to intentionally obstruct the work of our sworn immigration enforcement officers, to intentionally use every power the legislature has to undermine the duly-established immigration law of America," Mr Sessions told a California Peace Officers Association conference.
The lawsuit, filed late on Tuesday in federal court in Sacramento, takes aim at three state laws passed last year that the Justice Department contends violates the US Constitution and the supremacy of federal law over state law.
Mr Trump has made fighting illegal immigration and cracking down on illegal immigrants already in the United States a signature issue, first as a candidate and now as president. Part of that effort involves a Justice Department crackdown on primarily Democratic-governed cities and states that Mr Sessions calls "sanctuaries" that protect illegal immigrants from deportation.
'Law of the land'
"Immigration law is the province of the federal government," Mr Sessions said.
"There is no nullification. There is no secession. Federal law is the supreme law of the land," he added.
Other leading California Democrats also blasted the Trump administration.
US Senator Dianne Feinstein said the administration is simply looking to score points with Mr Trump's political supporters. "ICE should not be targeting parents who have lived in this country for decades, arresting them as they take their children to school," Ms Feinstein said in a statement.
Mr Sessions singled out Democratic Oakland Mayor Libby Schaaf, accusing her of actively seeking to help illegal immigrants avoid ICE.
Last month, Ms Schaaf issued a statement alerting local residents that ICE was preparing to conduct an operation in the area, saying it was her moral obligation. A few days later, ICE announced the arrest of more than 150 people for immigration violations in the San Francisco-Oakland area, saying about half had additional criminal convictions.
The White House has called Ms Schaaf's actions "outrageous" and said the Justice Department was reviewing the matter.
"Here's my message for Mayor Schaaf: How dare you. How dare you needlessly endanger the lives of law enforcement officers to promote your radical open-borders agenda," Mr Sessions said on Wednesday.
Mr Sessions also called Democratic California Lieutenant Governor Gavin Newsom an embarrassment for supporting the mayor's actions.