The mayor of Chicago has signed an order detailing how the city will resist a potential immigration crackdown threatened by the Trump administration.

"We do not need nor want an unconstitutional and illegal military occupation of our city," said Mayor Brandon Johnson, a Democrat.

The order directs city agencies on how to respond to possible immigration enforcement actions.

Trump has already deployed about 2,000 troops in Washington DC, and has threatened to extend the order to Chicago, which he says is a "mess".

There are also reports that the administration is planning to surge the number of federal immigration agents in the city.

A White House spokeswoman described the order as "a publicity stunt".

The order is the latest chapter in an escalating feud between the White House and state and local officials in Illinois over violent crime and immigration.

It demands that Trump and federal agents "stand down from any attempts to deploy the US Armed Forces" in the city.

The order also restates a number of existing city policies, including requirements that law enforcement officers wear body cameras and identifying information, and a ban on wearing masks.

Immigration and Customs Enforcement (ICE) officers have been sharply criticised in other cities for concealing their identities.

Johnson said city officials would help residents understand their rights if they encounter immigration enforcement, while ruling out allowing local officers to participate in joint patrols with federal agents.

Local officials say more than one in five Chicago residents is an immigrant, with more than half coming from Latin American countries. It is unclear how many are living in the city without official documentation.

Trump, a Republican, has said America's third-largest city as "a killing field", arguing crime in the city constitutes an emergency.

His threats to deploy the National Guard have been described as an abuse of power by Illinois Governor JB Pritzker.

"Donald Trump is attempting to manufacture a crisis, politicise Americans who serve in uniform, and continue abusing his power to distract from the pain he is causing working families," said Pritzker, a Democrat.

White House spokeswoman Abigail Jackson said officials in Chicago were making fighting crime a partisan issue.

"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."