CHICAGO (CBS) — With city attorneys set to defend Chicago’s “welcoming city” ordinance before a federal appeals court on Friday, Mayor Rahm Emanuel remained defiant Wednesday as the Trump administration has threatened criminal action against the mayors of so-called “sanctuary cities.”

Thomas Homan, the acting director of U.S. Immigration and Customs Enforcement, said earlier this month elected officials who run local governments that don’t cooperate with federal immigration authorities should be charged with crimes.

Chicago’s “Welcoming City Ordinance” protects undocumented immigrants from being held for immigration authorities, unless they have been convicted of a serious crime or are being sought on a criminal warrant. The ordinance also prohibits Chicago police from allowing U.S. Immigration and Customs Enforcement agents from using city facilities for interviews or investigations, and bars officers from replying to ICE inquiries or speaking to ICE officials about someone’s custody status or release date.

Despite Homan’s comments, and Attorney General Jeff Sessions’ plan to strip sanctuary cities of federal law enforcement grants, Emanuel has not backed down on maintaining limits on local authorities cooperating with the feds when trying to deport undocumented immigrants.

“What are you going to do, arrest mayors because they’re making sure that their residents are safe, secure, and their kids have a future?” he said. “Not only will it not stand in the court – the legal court – it will not stand in the court of public opinion, because it’s turning its back on everything we believe in.”

The city has sued Sessions over the Justice Department’s plan to withhold federal law enforcement grants from sanctuary cities.

A federal judge in September blocked the Trump administration’s rules requiring sanctuary cities to cooperate with federal immigration agents to get public safety grants. The White House has appealed that ruling, and the 7th Circuit Court of Appeals was scheduled to hear oral arguments on Friday.