National Guard troops arrived in downtown Los Angeles on Sunday after being ordered into the city by President Trump in response to a weekend of violent clashes between law enforcement officers and protesters triggered by immigration enforcement operations in the area on Friday.

California Highway Patrol officers pushed protesters off Highway 101 in Los Angeles on Sunday using flash bang stun grenades and tactical positioning after hundreds of people spilled onto one of the city’s main thoroughfares.

The move appeared to be the first time in decades that a state’s national guard was activated without a request from its governor.