From ABC News.

Heavily armed federal border agents and U.S. troops descended upon MacArthur Park in Los Angeles on Monday afternoon as part of an immigration raid that appeared to turn up mostly empty.

The operation, which included 90 armed troops and 17 military Humvees, displaced a summer day camp, according to Los Angeles Mayor Karen Bass, who said the only point of the operations appeared to be "a political agenda of provoking fear and terror."

"To me, this is another example of the administration ratcheting up chaos by deploying what looked like a military operation in an American city," Bass said.

According to a post on X by the Defense Department, U.S. military personnel were on the ground to ensure the safety of federal agents.

“We will protect federal law enforcement and assist by establishing a security perimeter,” DOD wrote.

California Gov. Gavin Newsom, speaking at a news conference to discuss recovery from the wildfires that devastated the city earlier this year, called the operation "theater."

“What a disgrace, what’s happening in MacArthur Park. What theater. On the six-month anniversary, after all, of these fires — that’s the message from the polluted heart of the President of the United States, the polluted heart of [White House Deputy Chief of Staff] Stephen Miller,” Newsom said.

It was not immediately clear who or what was targeted. Bass posted a video of agents, some on horseback, moving in what she called a "skirmish line" across the mostly empty park.

The mayor said she didn’t believe anyone was detained, "but then again, I don’t think the goal is to detain. I think the goal is to spread fear. I think that’s what it is. It’s to terrorize Angelenos. It’s to say to immigrants that are in our city of immigrants that they need to stay home, they shouldn’t go to work, they shouldn’t go to school, because we’re coming after you."

Hours after the raid, federal authorities wouldn’t say why they were at the park or what they were looking for, or if any arrests were made.

Defense officials had said the troops were deployed to set up a security perimeter to protect federal law enforcement officials against potentially hostile crowds.

All of the troops involved in the operation were activated members of the California National Guard.

The operation included some 17 Humvees, four military cargo trucks and two military ambulances, officials said.

The armed troops were told in advance of the raid that they could defend themselves and federal employees if needed. If a person was a threat, the troops could detain the individual briefly before handing them off to law enforcement, officials said.

Earlier this summer, Trump deployed some 4,700 troops to California under a law known as Title 10, which allows the use of military forces to protect federal personnel and federal property.