A battalion of 500 U.S. Marines are mobilizing to Los Angeles to respond to anti-immigration enforcement riots.

The Marines will be tasked with protecting federal property and federal personnel, according to a senior defense official, and the deployment is open-ended.

The Marines will not be carrying out a law enforcement role, but it’s unclear what their use of force rules are if protesters throw things or spit at them.

The new deployment comes after President Donald Trump sent some 2,000 National Guardsmen to the riot-racked city over the weekend.

The Marines are from the 2nd Battalion, 7th Marines at Twentynine Palms, California.