Police declared all of downtown Los Angeles to be an unlawful assembly area and ordered protesters to go home on Sunday night after a third day of violence hit demonstrations against U.S. President Donald Trump's immigration policy.

U.S. National Guard troops — deployed by Trump over the weekend to help quell the protests in a move that California Gov. Gavin Newsom called unlawful — guarded federal government buildings on Sunday.

The unrest in Los Angeles has become a major flash point in Trump's signature effort to clamp down on illegal immigration.