WASHINGTON >> The Trump administration is suing to block California laws that extend protections to people living in the U.S. illegally, the most aggressive move yet in its push to force so-called sanctuary cities and states to cooperate with immigration authorities. California officials remained characteristically defiant, vowing to defend their landmark legislation.

Justice Department officials said today that a trio of state laws that, among other things, bar police from asking people about their citizenship status or participating in federal immigration enforcement activities are unconstitutional and have kept federal agents from doing their jobs. Attorney General Jeff Sessions is expected to announce the lawsuit Wednesday at an annual gathering of law enforcement officers in Sacramento. It names as defendants the state of California, Gov. Jerry Brown and Attorney General Xavier Becerra.

“I say, bring it on,” said California Senate President Pro Tem Kevin de Leon, a Los Angeles Democrat who wrote the sanctuary state bill.

It is the latest salvo in an escalating feud between the Trump administration and California, which has resisted the president on issues like taxes and marijuana policy and defiantly refuses to help federal agents detain and deport undocumented immigrants. U.S. Immigration and Customs Enforcement has said it will increase its presence in California, and Sessions wants to cut off funding to jurisdictions that won’t cooperate.

The lawsuit is being filed as the Justice Department also reviews Oakland Mayor Libby Schaaf’s decision to warn of an immigration sweep in advance, which ICE said allowed hundreds of immigrants to elude detention.

The state laws being challenged were a response to President Donald Trump’s hawkish immigration policies and widespread fear in immigrant communities following a campaign in which he promised to sharply ramp up the deportation of people living in the U.S. illegally. The decision to sue California shows Sessions and Trump remain aligned on this priority, even as their relationship has recently deteriorated, with Trump attacking his attorney general and Sessions pushing back.

Brown mimicked Trump on Twitter tonight, writing: “At a time of unprecedented political turmoil, Jeff Sessions has come to California to further divide and polarize America. Jeff, these political stunts may be the norm in Washington, but they don’t work here. SAD!!!”

One of California’s laws prohibits employers from letting immigration agents enter worksites or view employee files without a subpoena or warrant, an effort to prevent workplace raids. Another stops local governments from contracting with for-profit companies and ICE to hold immigrants. Justice Department officials, speaking to reporters today, said that violates the Constitution’s supremacy clause, which renders invalid state laws that conflict with federal ones.

The Supreme Court reinforced the federal government’s primacy in enforcing immigration law when it blocked much of Arizona’s tough 2010 immigration law on similar grounds. The high court found several key provisions undermined federal immigration law, though it upheld a provision requiring officers, while enforcing other laws, to question the immigration status of people suspected of being in the country illegally.

In this case, California “has chosen to purposefully contradict the will and responsibility of Congress to protect our homeland,” Homeland Security Secretary Kirstjen Nielsen said in a statement.

Sessions has blamed sanctuary city policies for crime and gang violence and announced in July that cities and states could only receive certain grants if they cooperate with immigration agents. California is suing to force the administration to release one such grant. The state wants a judge to certify that its laws are in compliance with federal immigration law.

Defenders of sanctuary policies say they increase public safety by promoting trust between immigrant communities and law enforcement, while allowing police resources to be used to fight other crimes.

“We’re America’s economic engine, and it is precisely because we embrace the cultural gifts immigrants bestow us and their diversity that they become the backbone of our economy,” de Leon said.

Sessions’ audience Wednesday includes members of the California Peace Officers’ Association and groups representing police chiefs, sheriffs, district attorneys, narcotics investigators and the California Highway Patrol.

The groups’ members have often been split on sanctuary policies. None of the groups favored the state law restricting cooperation with immigration officials, but only the California State Sheriffs’ Association was actively opposed and some individual officials voiced support.

Protesters from labor unions, the Democratic Party and immigrant rights organizations planned to rally along with some state and local elected officials outside the hotel where Sessions will speak.

Becerra is speaking to the same law enforcement organizations later Wednesday.

Becerra, a Democrat who is up for election in November, has been sharply critical of Republicans Trump and Sessions, particularly on immigration policies.

He has said federal authorities need to have warrants before collecting information from state employers or entering nonpublic areas.