Chicago Mayor Rahm Emanuel announced Friday he plans to sue the Trump administration for threatening to withhold public safety federal grant money because of the city's immigration policy.

The city will argue in federal court that Attorney General Jeff Sessions cannot withhold funding for Edward Byrne Memorial Justice Assistance Grant Programs -- a crime-fighting source for local governments -- to cities that limit their cooperation with requests from Immigration and Customs Enforcement.

Emanuel announced the lawsuit during an interview on "Connected to Chicago" on WLS radio-890.

"We're not going to actually auction off our values as a city, so Monday morning the City of Chicago is going to court, we're going to take the Justice Department to court based on this," said Emanuel, a Democrat and former chief of staff to President Barack Obama. "We find it unlawful and unconstitutional to be, as a city, coerced on a policy."

According to the Chicago Tribune, Byrne Justice Assistance Grants represent a small portion of funding to the city.

The city this year planned to get $3.2 million from the program, which would mostly be used to buy police vehicles. That figure amounts to roughly three-hundredths of 1 percent of the entire $9.8 billion city budget.

Sessions announced last month that the Justice Department will refuse to give Byrne Justice Assistance Grants to so-called sanctuary cities that limit the circumstances in which they work with federal immigration authorities to deport illegal immigrants in local custody.

Chicago prohibits ICE officials from access to people in police custody unless they are wanted on a criminal warrant or have serious criminal convictions.

"As part of accomplishing the Department of Justice's top priority of reducing violent crime, we must encourage these 'sanctuary' jurisdictions to change their policies and partner with federal law enforcement to remove criminals," Sessions said in a July 25 statement. "From now on, the Department will only provide Byrne JAG grants to cities and states that comply with federal law, allow federal immigration access to detention facilities, and provide 48 hours notice before they release an illegal alien wanted by federal authorities."

Federal appeals courts have ruled that complying with detainer requests -- as cooperating with requests from ICE are known -- is optional for local governments.

California Attorney General Xavier Becerra, a Democrat, is also considering suing the Justice Department for the same reason, according to a report Friday, claiming Sessions' conditions for grant recipients are illegal.