The city of Chicago is filing a lawsuit against the U.S. Justice Department.

Chicago Mayor Rahm Emanuel announced Sunday that his city would sue the Trump administration for vowing to block federal grant money to sanctuary cities that do not comply with federal immigration law. 

A new set of conditions was added to the grant money application requiring local police departments to assist in federal immigration actions. 

The new rule would force local police to report about illegal immigrants released from police custody. 

Chicago officials allege that they’re unconstitutional and “effectively federalize local detention facilities and violate the Fourth Amendment.”

The mayor said the city won’t be “blackmailed” into changing its values as a welcoming city. 

“Chicago will not let our police officers become political pawns in a debate,” Emanuel said. “Chicago will not let our residents have their fundamental rights isolated and violated. And Chicago will never relinquish our status as a welcoming city.”

“The city of Chicago may be the first to bring a lawsuit, but I’m also confident we will not be the last,” he added. 

The DOJ has responded to that announcement. 

“In 2016, more Chicagoans were murdered than in New York City and Los Angeles combined. So it’s especially tragic that the mayor is less concerned with that staggering figure than he is spending time and taxpayer money protecting criminal aliens and putting Chicago’s law enforcement at greater risk,” department spokeswoman Sarah Isgur Flores told the Chicago Sun-Times.

The lawsuit is centered around the FY2017 Edward Byrne Memorial Justice Assistance Grant, or JAG, which provides federal funding to support local law enforcement efforts. 

Last year, Chicago received $2.3 million in JAG funds. The city is depending on $3.2 million from the program to buy police vehicles, according to Fox News.