The lawsuit, which also names the state of Illinois, is the latest effort to crack down on places that limit cooperation between federal immigration agents and local police. It follows the federal government’s threats of criminal charges and funding cuts to what are known as sanctuary cities.

“The conduct of officials in Chicago and Illinois minimally enforcing — and oftentimes affirmatively thwarting — federal immigration laws over a period of years has resulted in countless criminals being released into Chicago who should have been held for immigration removal from the United States,” according to the lawsuit filed in Chicago’s federal court.

Targeting sanctuary cities

President Donald Trump has often singled out Chicago and Illinois because they have some of the nation’s strongest protections for immigrants. Top administration officials last month visited the city to launch stepped up immigration enforcement and showcased footage of “border czar” Tom Homan making arrests.

The aggressive approach and harsh rhetoric have been heavily criticized for stoking fears in immigrant communities and feeding false claims about crime among immigrants.

While several high-profile and violent crimes involving people in the U.S. illegally have been in the news in recent months, there is nothing to support the allegation that it happens daily. Studies have found that people living in the U.S. illegally are less likely than native-born Americans to have been arrested for violent, drug and property crimes.

Still, the sentiment is the cornerstone of Trump’s agenda. The first bill he signed of his new administration, named after slain Georgia nursing student Laken Riley, requires the detention of immigrants in the country illegally who are accused of theft and violent crimes.

Federal funding cuts

Hours after new Attorney General Pam Bondi was sworn in Wednesday, she ordered an end to Department of Justice grants for jurisdictions that “unlawfully interfere with federal law enforcement.”

Courts, however, have repeatedly upheld the legality of the range of sanctuary laws. The laws do not allow local law enforcement to actively interfere with federal operations. The first Trump White House also tried to deny public safety grants to sanctuary jurisdictions, but courts also largely rejected those attempts.

California Democratic Attorney General Rob Bonta said he is monitoring the directive’s implementation.

“We won’t hesitate to respond if the Trump administration attempts to delay or unlawfully condition vital public safety funding for state and local law enforcement,” he said in a statement.

Connecticut Attorney General William Tong, a Democrat, used an argument that Republicans have used against members of his party, saying pausing funding to sanctuary jurisdictions is defunding the police.

“This is yet another attempt by the Trump administration to defund police and distract local law enforcement from serious public safety threats, including gun violence, reckless driving, domestic violence and the opioid epidemic,” Tong said in a statement.

The administration has already made clear that legal precedent won’t necessarily stand in its way. Lawyers say that simply filing lawsuits can intimidate jurisdictions to back away from their sanctuary laws.

Immigration advocates expect the administration to use a range of political tools against sanctuary jurisdictions, from legislation to Bondi’s directives to threats to restrict funding from agencies including the Department of Transportation.

“This is going to be an ongoing attack on all fronts and in multiple agencies,” Kerri Talbot, the co-executive director of the Immigration Hub, a pro-immigration policy group, told reporters.

Sanctuary cities vow to fight back

The lawsuit against Chicago claims that local laws run counter to federal laws by restricting “local governments from sharing immigration information with federal law enforcement officials” and preventing immigration agents from identifying “individuals who may be subject to removal.”

Heavily Democratic Chicago has been a sanctuary city for decades and has beefed up its laws several times, including during Trump’s first term in 2017. That same year, then-Gov. Bruce Rauner, a Republican, signed more statewide sanctuary protections in law, putting him at odds with his party.

Chicago Mayor Brandon Johnson said Chicago will remain a welcoming city. He and other mayors plan to testify next month at a congressional hearing on sanctuary cities. In recent months, Chicago has helped host trainings for people to learn their rights when it comes to immigration agents and publicized the information at public transit stations.

“The safety and security of Chicago residents remains the priority,” he said in a statement Thursday. “Chicago will continue to protect the working people of our city and defend against attacks on our longstanding values.”

Illinois Democratic Gov. JB Pritzker said the state has always complied with the law.

“Unlike Donald Trump, Illinois follows the law,” Pritzker’s office said in a statement. “Instead of working with us to support law enforcement, the Trump Administration is making it more difficult to protect the public, just like they did when Trump pardoned the convicted January 6 violent criminals.”

The lawsuit also names Cook County, where Chicago is located, and its sheriff.

Cook County Board President Toni Preckwinkle said in a statement that the nation’s second-most populous county, “remained committed to being a fair and welcoming community for all residents.”

Sheriff Tom Dart issued a statement saying his office doesn’t pass or enact immigration legislation and follows all laws.