WASHINGTON  — The District of Columbia on Thursday sued to stop President Donald Trump’s deployment of National Guard during his law enforcement interventionin Washington, with the city’s top legal official saying the surge of troops amounts to a forced “military occupation.”

Brian Schwalb, the district’s elected attorney general, said in the federal lawsuit that the deployment, which now involves more than 1,000 troops, is an illegal use of the military for domestic law enforcement.

“No American jurisdiction should be involuntarily subjected to military occupation,” Schwalb wrote.

The Republican president has already said he plans to send the National Guard into Chicago and Baltimore, despite staunch opposition in those Democrat-led cities, and the White House said deploying the Guard to protect federal assets and assist law enforcement is within Trump’s authority as president.

“This lawsuit is nothing more than another attempt — at the detriment of DC residents and visitors — to undermine the President’s highly successful operations to stop violent crime in DC,” spokeswoman Abigail Jackson said.

Members of the D.C. National Guard have had their orders extended through December, according to a Guard official. While that does not necessarily mean all those troops will serve that long, it is a strong indication that their role will not wind down soon.