The troops included members of the 79th Infantry Brigade Combat Team, according to a social media post from the Department of Defence that showed dozens of National Guard members with long guns and an armoured vehicle.

Early on Sunday, the deployment was limited to a small area in downtown Los Angeles. The protests have been relatively small and limited to a downtown section. The rest of the city of 4 million people is largely unaffected.

Their arrival follows clashes near a Home Depot in the heavily Latino city of Paramount, south of Los Angeles. As protesters sought to block Border Patrol vehicles, with some hurling rocks and chunks of cement, federal agents unleashed tear gas, flash-bang explosives and pepper balls.

Tensions were high after a series of sweeps by immigration authorities the previous day, as the weeklong tally of immigrant arrests in the city climbed past 100. A prominent union leader was arrested while protesting and accused of impeding law enforcement.

On Sunday morning, Homeland Security Secretary Kristi Noem said the National Guard would “keep peace and allow people to be able to protest but also to keep law and order.”

In a signal of the administration’s aggressive approach, Defence Secretary Pete Hegseth also threatened to deploy active-duty Marines “if violence continues” in the region.

The move came over the objections of Governor Gavin Newsom, marking the first time in decades that a state’s national guard was activated without a request from its governor, according to the Brennan Centre for Justice.

Newsom, a Democrat, said Trump’s decision to call in the National Guard was “purposefully inflammatory.”

He described Hegseth’s threat to deploy Marines on American soil as “deranged behaviour”.

Trump’s order came after clashes in Paramount and neighbouring Compton, where a car was set on fire.

Protests continued into the evening in Paramount, with several hundred demonstrators gathered near a doughnut shop, and authorities holding up barbed wire to keep the crowd back.

Crowds also gathered again outside federal buildings in downtown Los Angeles, including a detention centre, where local police declared an unlawful assembly and began to arrest people.