The Pentagon is scrambling to establish rules to guide U.S. Marines who could be faced with the rare and difficult prospect of using force against citizens on American soil, now that the Trump administration is deploying active duty troops to the immigration raid protests in Los Angeles.

The U.S. military is set to temporarily deploy about 700 Marines to Los Angeles while additional National Guard troops arrive in the city, a U.S. official told Reuters on Monday. About 300 California National Guard troops were deployed to the streets of Los Angeles on Sunday to help quell a third day of protests over President Donald Trump's immigration enforcement,