The Trump administration filed a lawsuit against California on Tuesday to challenge its policies protecting undocumented immigrants.

The Department of Justice sued the state of California, along with Gov. Jerry Brown and state Attorney General Xavier Becerra, in response to three state laws that administration officials say obstruct federal immigration laws and are in violation of the Constitution’s supremacy clause, which states that federal law has precedence over state legislation.

The three laws in question, all of which were signed into law within the last year, establish protections for immigrants at risk of deportation. Senate Bill 54 restricts law enforcement from notifying federal immigration agents of release dates of immigrants held in jail and Assembly Bill 103 requires the California attorney general to inspect detention facilities where immigrants facing deportation are held. Assembly Bill 450 prohibits employers from cooperating with federal immigration agents and requires employers to notify workers before federal agents conduct inspections.

Attorney General Jeff Sessions delivered a speech on Wednesday to several hundred law enforcement officers in Sacramento announcing the lawsuit.

“A refusal to apprehend and deport those, especially the criminal element, effectively rejects all immigration law and creates an open-borders system,” Sessions said in his speech. “The law is in the books, and its purpose is clear. There is no nullification. There is no secession. Federal law is ‘the supreme law of the land.’”

Sessions’ speech was met with a protest of few hundred people in Sacramento. The lawsuit also prompted backlash from Gov. Brown, who stated “the attorney general is igniting a reign of terror” against immigrants in a news conference following Sessions’ speech.

“This is basically going to war against the state of California, the engine of the American economy,” Brown said at the news conference. “It’s not wise, it’s not right and it will not stand.”

The lawsuit may be the first of more to come, as officials from the Department of Justice said they would not rule out the possibility of lawsuits against other states and localities that have enacted sanctuary legislation to protect immigrants from federal action.