LOS ANGELES (AP) — Tensions in Los Angeles heightened on Sunday as thousands took to the streets in response to President Donald Trump’s decision to deploy the National Guard. Protesters blocked major freeways and set self-driving cars on fire, leading law enforcement to use tear gas, rubber bullets, and flash bangs to disperse the crowd.

As evening approached, many protesters left the area when police declared an unlawful assembly, which typically precedes officers making arrests of those who remain. Some individuals threw objects at police from behind a makeshift barrier spanning a street, while others hurled pieces of concrete, rocks, electric scooters, and fireworks at California Highway Patrol officers and their vehicles on the closed southbound 101 Freeway. Officers sought shelter under an overpass.

Sunday’s demonstrations in Los Angeles, a vast city with a population of 4 million, focused largely in the downtown area. It marked the third and most intense day of protests against Trump’s immigration policies in the region. The arrival of about 300 National Guard troops caused further anger and anxiety among many residents.

The Guard was deployed specifically to protect federal buildings, including the downtown detention center where protesters concentrated.

Los Angeles Police Chief Jim McDonnell said officers were “overwhelmed” by the remaining protesters. He said they included regular agitators who show up at demonstrations to cause trouble.

Several dozen people were arrested throughout the weekend of protest. One was detained Sunday for throwing a Molotov cocktail at police, and another for ramming a motorcycle into a line of officers.

Trump responded to McDonnell on Truth Social, telling him to arrest protesters in face masks.

“Looking really bad in L.A. BRING IN THE TROOPS!!!” he wrote.

Clashes escalate as National Guard troops arrive

In Los Angeles on Sunday morning, National Guard troops stood shoulder to shoulder, carrying long guns and riot shields as protesters shouted “shame” and “go home.” After some closely approached the guard members, another set of uniformed officers advanced on the group, shooting smoke-filled canisters into the street.

Minutes later, the Los Angeles Police Department fired rounds of crowd-control munitions to disperse the protesters, who they said were assembled unlawfully. Much of the group then moved to block traffic on the 101 freeway until state patrol officers cleared them from the roadway by late afternoon.

Nearby, at least four self-driving Waymo cars were set on fire, sending large plumes of black smoke into the sky and exploding intermittently as the electric vehicles burned. By evening, police had issued an unlawful assembly order shutting down several blocks of downtown Los Angeles.

Flash bangs echoed out every few seconds into the evening.