Trump had already mobilized 2,000 National Guard members to the country's second most populous city on Saturday, with some 300 taking up positions protecting federal buildings and officers on Sunday.

On Monday -- the fourth day of protests against immigration raids in the city that have seen some scuffles with law enforcement -- the Trump administration announced the mobilization of the 700 Marines as well as an "additional" 2,000 National Guard.

A senior administration official told AFP that "active-duty US Marines from Camp Pendleton will be deployed to Los Angeles to help protect federal agents and buildings."

The official first gave a figure of 500 Marines, but later updated the number to 700.

Deploying active duty military personnel like US Marines into a community of civilians within the United States is a highly unusual measure.

The US military separately confirmed the deployment of "approximately 700 Marines" from an infantry battalion following the unrest.

They would "seamlessly integrate" with National Guard forces that Trump deployed to Los Angeles on Saturday without the consent of California's Democratic Governor Gavin Newsom.

The deployment was meant to ensure there were "adequate numbers of forces," it added.

Pentagon spokesman Sean Parnell then announced the mobilization of "an additional 2,000 California National Guard to be called into federal service to support ICE (Immigration and Customs Enforcement) & to enable federal law-enforcement officers to safely conduct their duties."

It was not immediately clear if the "additional" 2,000 guardsmen were on top of the 2,000 that had already been mobilized, or only the 300 that were already in the streets of Los Angeles.

Newsom wasted little time accusing the president of sowing "chaos" in Los Angeles.

"Trump is trying to provoke chaos by sending 4,000 soldiers onto American soil," the governor posted on X.

Earlier, he slammed the "deranged" decision by "dictatorial" Trump to send in Marines.

US Defense Secretary Pete Hegseth had first mentioned that the Marines could be deployed on Saturday.