The Chicago Police Department will be barred from helping federal authorities with civil immigration enforcement or any related patrols, traffic stops and checkpoints during the surge, according to an executive order signed by Mayor Brandon Johnson.

The mayor directed all city departments to guard the constitutional rights of Chicago residents “amidst the possibility of imminent militarised immigration or National Guard deployment by the federal government.”

When asked during a news conference about federal agents who are presumably “taking orders,” Johnson replied: “Yeah, and I don’t take orders from the federal government.”

Johnson also blocked Chicago police from wearing face coverings to hide their identities, as most federal Immigration and Customs Enforcement officers have adopted since the Trump administration took charge this year.

The federal surge into Chicago could start as early as September 5 and last about 30 days, according to two US officials, who spoke on the condition of anonymity to discuss plans that had not been made public.

The officials described the immigration crackdown as part of a larger effort to expand the federal law enforcement presence in major Democratic-run cities, as it did this summer in Los Angeles.

On Saturday, President Donald Trump commented about Chicago crime and Illinois Governor JB Pritzker on his Truth Social site: “Six people were killed, and 24 people were shot, in Chicago last weekend, and JB Pritzker, the weak and pathetic Governor of Illinois, just said that he doesn’t need help in preventing CRIME. He is CRAZY!!! He better straighten it out, FAST, or we’re coming! MAGA. President DJT”

Unlike the recent federal takeover of policing in Washington, DC, the Chicago operation is not expected to rely on the National Guard or military and is focused exclusively on immigration instead of being cast as part of a broad campaign against crime, the officials said.

Chicago is home to a large immigrant population, and both the city and the state of Illinois have some of the country’s strongest rules against cooperating with federal immigration enforcement efforts.

That has often put the city and state at odds with Trump’s mass deportation agenda.

Johnson’s order builds on the city’s longtime stance, saying neither Chicago nor Illinois officials have sought or been consulted on the federal presence and demanding Trump stand down on those plans.

Johnson had harsh words for Trump during his news conference, accusing the president of “behaving outside the bounds of the Constitution” and seeking a federal presence in blue cities as retribution against his political rivals.

“He is reckless and out of control,” Johnson said.

“He’s the biggest threat to our democracy that we’ve experienced in the history of our country.”

In response, the White House insisted the potential flood of federal agents was about “cracking down on crime.”

“If these Democrats focused on fixing crime in their own cities instead of doing publicity stunts to criticise the President, their communities would be much safer,” White House spokeswoman Abigail Jackson said in an email.