The Justice Department is suing California over immigration laws that oppose President Trump’s agenda, its boldest attack yet on the state.

The Trump administration escalated what had been a war of words over California’s immigration agenda, filing a lawsuit late Tuesday that amounted to a pre-emptive strike against the liberal state’s so-called sanctuary laws.

The Justice Department sued California; Gov. Jerry Brown; and the state’s attorney general, Xavier Becerra, over three state laws passed in recent months, saying they made it impossible for federal immigration officials to do their jobs and deport criminals who were born outside the United States. The Justice Department called the laws unconstitutional and asked a judge to block them.

The lawsuit was the department’s boldest attack yet against California, one of the strongest opponents of the Trump administration’s efforts to curb immigration. It also served as a warning to Democratic lawmakers and elected officials nationwide who have enacted sanctuary policies that provide protections for undocumented immigrants.