A US senator has been dragged to the ground and handcuffed by federal agents in a dramatic incident at a media conference in Los Angeles.

Senator Alex Padilla, a Democrat from California, was forcibly ejected from Thursday’s event after he tried to ask Department of Homeland Security Secretary Kristi Noem a question during her event in Los Angeles, Reuters video showed.

Noem – who used the same event to pledge to “liberate” Los Angeles – said later that Padilla had not identified himself as a senator during the scuffle. But the video clearly shows him doing so.

“I’m Senator Alex Padilla,” he shouts as he is led out of the room.

“I have questions for the secretary.”

She met Padilla later on Thursday (local time) and said the two had agreed to talk further.

Noem was in LA after days of protests against the Trump administration’s immigration raids.

President Donald Trump, a Republican, has deployed the National Guard and the Marines, over the objections of the state’s Democratic governor, Gavin Newsom, and other officials, who say the move is unnecessary and illegal.

Trump has defended his decision, saying if he had not done so the city would be in flames.

The protests have been mostly peaceful, punctuated by incidents of violence and restricted to a few city blocks.

“We’re going to stay here and build our operations until we make sure we liberate the city of Los Angeles,” Noem said.

Los Angeles Mayor Karen Bass called on Immigration and Customs Enforcement officers to stand down from the intensified series of raids that led to the protests, saying the local economy could be harmed as immigrants stayed home from work and school for fear of being snatched off the streets.

“The peace that we need to have happen needs to begin in Washington, and we need to stop the raids,” Bass said, as those alongside her broke out in a chant of “Stop the raids”.

“Peace begins with ICE leaving Los Angeles,” said Bass, who nonetheless has imposed a night-time curfew over 2½ square kilometres of downtown L.A.

Bass also expressed support for Padilla who, video showed, was forced to lie on the ground in a corridor outside the conference room by federal agents. They then handcuffed his hands behind his back.

In a statement, the department said US Secret Service agents believed Padilla was an “attacker” who did not comply with orders to back away.

“I was there peacefully. At one point I had a question, and so I began to ask a question. I was almost immediately forcibly removed from the room. I was forced to the ground, and I was handcuffed. I was not arrested. I was not detained,” Padilla said later.

“If this is how the Department of Homeland Security responds to a senator with a question, you can only imagine what they’re doing to farmers to cooks to day labourers throughout the Los Angeles community and throughout California and throughout the country.”

Noem said later on X that she met Padilla, and though she accused him of “creating a scene”, they exchanged phone numbers and agreed to keep talking.

The clash came as the military said 700 US Marines would be on LA’s streets by Thursday or Friday to support up to 4000 National Guard troops in protecting federal property and federal agents, including on immigration raids.

The state of California sought a federal court order on Thursday to prevent troops patrolling the streets of Los Angeles and to limit their role to protecting federal personnel and property.

Americans are divided over Trump’s decision to activate the military, according to a Reuters/Ipsos poll that showed 48 per cent of respondents agreed with a statement that he should “deploy the military to bring order to the streets” when protests turn violent. Some 41 per cent disagreed.

-with AAP