Pentagon was scrambling Monday 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.

U.S. Northern Command said it is sending 700 Marines into the Los Angeles area to protect federal property and personnel, including federal immigration agents. The 2nd Battalion, 7th Marines are coming from Twentynine Palms, California, and will augment about 4,100 National Guard members already in LA or authorized to be deployed there to respond to the protests.