Security forces have clashed with protesters in Los Angeles as National Guard troops deployed by Donald Trump fanned out across the city on the third day of unruly protests over federal immigration raids.

Trump, who has made clamping down on illegal migration a key plank of his second term, vowed the troops would ensure “very strong law and order,” while appearing to leave the door open to deploying soldiers in other cities.

The United States military said 300 Guardsmen from the 79th Infantry Brigade Combat Team had been sent to three separate locations in the greater Los Angeles area, and were “conducting safety and protection of federal property and personnel”.

Helmeted troops in camouflage gear and carrying guns were stationed at a federal detention centre in downtown Los Angeles, where they joined Department of Homeland Security forces.

Pepper spray and tear gas were fired into a small crowd – including at journalists – as forces moved protesters back to allow a convoy of vehicles to enter the detention centre.

Immigration and Customs Enforcement (ICE) and Department of Homeland Security (DHS) agents take security measures as protests continue in Paramount, California, and downtown Los Angeles, California.
Photo / Getty Images

Police later moved and pushed demonstrators away from the federal lines, using batons, flash-bang grenades and tear gas as they tried to disperse the crowd, some of whom spilled on to a major freeway, stopping traffic.

Trump, asked about the use of troops, hinted at a more widespread deployment in other parts of the country.

“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.”

Responding to a question about invoking the Insurrection Act – which would allow the military to be used as a domestic police force – Trump said: “We’re looking at troops everywhere. We’re not going to let this happen to our country”.

US President Donald Trump deployed 2,000 troops on June 7 to handle escalating protests against immigration enforcement raids in the Los Angeles area, a move the state's governor termed "purposefully inflammatory." Photo / Ringo Chiu, AFP

The deployment in California – the first over the head of a state governor since the Civil Rights era – was “purposefully inflammatory,” Governor Gavin Newsom said.

“We didn’t have a problem until Trump got involved. This is a serious breach of state sovereignty – inflaming tensions while pulling resources from where they’re actually needed. Rescind the order. Return control to California,” he wrote on X.

A joint statement by Democratic governors from across the country in support of Newsom said Trump’s use of the California National Guard was “an alarming abuse of power”.

The National Guard – a reserve military – is frequently used in natural disasters, and occasionally in instances of civil unrest, but almost always with the consent of local authorities.

Republicans lined up behind Trump to dismiss the pushback by Newsom and other local officials against the National Guard deployment.

“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”.

Demonstrators told AFP the purpose of the troops did not appear to be to keep order.

“I think it’s an intimidation tactic,” Thomas Henning said.

“These protests have been peaceful. There’s no one trying to do any sort of damage right now and yet you have the National Guard with loaded magazines and large guns standing around trying to intimidate Americans from exercising our first amendment rights.”

Estrella Corral said demonstrators were angry that hard-working migrants who have done nothing wrong were being snatched by masked immigration agents.

“This is our community, and we want to feel safe,” she told AFP.

“Trump deploying the National Guard is ridiculous. I think he’s escalating, he’s trying to make a show for his agenda.”

Marshall Goldberg, 78, told AFP deploying Guardsmen made him feel “so offended”.

A demonstrator reacts during clashes with law enforcement in Los Angeles, California on June 8. 
Photo / AFP

“We hate what they’ve done with the undocumented workers, but this is moving it to another level of taking away the right to protest and the right to just peaceably assemble,” he said.

Raids by the Immigration and Customs Enforcement (ICE) agency in other US cities have triggered small-scale protests in recent months, but the Los Angeles unrest is the biggest and most sustained against Trump’s immigration policies so far.

A CBS News poll taken before the Los Angeles protests showed a slight majority of Americans still approved of the immigration crackdown.

Mexico President Claudia Sheinbaum on Sunday defended migrants living north of the border insisting “Mexicans living in the United States are good men and women”.

- Agence France-Presse