CHICAGO/NEW YORK (Reuters) - Chicago will sue the Trump administration on Monday over threats to withhold public safety grant money from so-called sanctuary cities, escalating a pushback against a federal immigration crackdown, Mayor Rahm Emanuel announced on Sunday.

The federal lawsuit comes less than two weeks after Attorney General Jeff Sessions announced the U.S. Justice Department would bar cities from a certain grant program unless they allow immigration authorities unlimited access to local jails and provide 48 hours’ notice before releasing anyone wanted for immigration violations.

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

Edward Byrne Memorial Justice Assistance Grants provide money to hundreds of cities, and the Trump administration has requested $380 million in funding next year. Chicago, a regular target of Republican President Donald Trump because of its murder rate, expected to receive $3.2 million this year for purchasing equipment.

Emanuel said the lawsuit would prevent the Trump administration from setting a precedent that could be used to target other funding.

Under Trump and Sessions, the federal government has sought to crack down on sanctuary cities, which generally offer illegal immigrants safe harbor by declining to use municipal resources to enforce federal immigration laws. Dozens of local governments and cities, including New York, Los Angeles and Chicago, have joined the growing sanctuary movement.

The Justice Department said more Chicagoans were murdered last year than residents of Los Angeles and New York combined, and cited comments by Sessions last week saying sanctuary cities “make all of us less safe.”

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Justice Department spokeswoman Sarah Isgur Flores said in a Sunday statement: “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.”

Police and city officials in sanctuary cities have said deporting illegal immigrants who are not accused of serious crimes harms public safety by discouraging immigrants from coming forward to report crimes.

Chicago’s lawsuit is the first to challenge the department over the Byrne program, though city officials said they are in contact with other cities. California Attorney General Xavier Becerra is also considering a similar lawsuit, the Sacramento Bee has reported.

The Trump administration has already faced legal battles over its sanctuary city policies. Last month, a U.S. judge refused to revisit a court order that blocked Trump’s January executive order denying broader federal funds to such jurisdictions, in a case filed by San Francisco and the California county of Santa Clara.