WASHINGTON

President Donald Trump said Tuesday that he is open to invoking the Insurrection Act to expand his domestic deployments of American forces against the wishes of local officials amid a standoff with Democratic-led states and cities.

"It's been invoked before," Trump said. "If you look at Chicago, Chicago is a great city where there's a lot of crime, and if the governor can't do the job, we'll do the job. It's all very simple."

On Monday, Illinois and Chicago officials filed a lawsuit against the Trump administration seeking to block the deployment, arguing that Trump’s order to federalize state troops was unconstitutional. The lawsuit, submitted by Illinois Attorney General Kwame Raoul to the federal court in Chicago, described the move as “illegal, dangerous, and unconstitutional.”

The judge presiding over the case gave the Trump administration until midnight on Wednesday to respond.

Trump has so far declined to invoke the more than two centuries-old law, but said Monday he would do so "if necessary" as he faces mounting legal challenges to his deployments of US forces in major metropolises. The law permits the president to deploy active-duty military forces to carry out civilian law enforcement duties during exceptional circumstances.

The last time the 1807 law was invoked was during the 1992 Los Angeles riots that were sparked by the police beating of a Black man.

Trump told reporters Monday that he has not invoked the law "so far," but added that "we have an Insurrection Act for a reason."

"If I had to enact it, I'd do that if people were being killed, killed, and courts were holding us up, or governors or mayors were holding us up. Sure, I'd do that. I mean, I want to make sure that people aren't killed. We have to make sure that our cities are safe," he said.

Trump deployed the National Guard to Los Angeles and Washington, DC, and is in the works to do so in Memphis, Tennessee. He also sent hundreds of US Marines to Los Angeles in June to quell unrest caused by his immigration crackdown.