It has become the latest focal point in a national debate over immigration, protest rights and the use of federal force in domestic affairs.

Why did the protests start?

The ICE operations prompted a first round of protests, with raids occurring around a Home Depot store, as well as a garment factory and a warehouse, Salas said.

What was the initial response?

The protests started in downtown LA, before spreading on Sunday AEST to Paramount — a heavily Latino city in the LA county — and neighbouring Compton.

Around 300 troops arrived in LA amid ongoing protests, with some later facing off with demonstrators in front of a detention centre, as the situation escalated. Source: AAP / Eric Thayer/AP

As federal agents set up a staging area near a Home Depot in Paramount, demonstrators tried to block border patrol vehicles, with some hurling rocks and chunks of cement.

In response, agents in riot gear unleashed tear gas, flash-bang explosives and pepper balls.

When did Donald Trump step in?

It also accused the state’s Democrat leaders of “completely abdicat[ing] their responsibility to protect their citizens”.

Around 300 troops arrived in LA overnight, with some later facing off with protesters in front of the Metropolitan Detention Centre, as the situation escalated.

What is the national guard?

The last time the national guard was activated without a governor’s permission was in 1965, when then-president Lyndon B Johnson sent troops to protect a civil rights march in Alabama, according to the Brennan Center for Justice.

A woman waves a Mexican flag amid tear gas from law enforcement during a protest in the Paramount section of Los Angeles. Source: AAP / Eric Thayer/AP

What has the response been?

“His [Trump] movement doesn’t believe in democracy or protest — and if they get a chance to end the rule of law, they will take it.”

“I have no concern about that at all,” said Republican house speaker Mike Johnson, accusing Newsom of “an inability or unwillingness to do what is necessary”.

What’s next?

“You have violent people, and we are not going to let them get away with it,” he told reporters. “I think you’re going to see some very strong law and order.”