US senator dragged out of LA news conference and handcuffed

Democratic US Senator Alex Padilla was forcibly removed from a news conference held by Homeland Security Secretary Kristi Noem in Los Angeles on Thursday and placed in handcuffs.

Noem was giving an update on immigration enforcement after nearly a week of protests in the city, when Senator Padilla interrupted and started shouting a question.

"I'm Senator Alex Padilla," he said as he was confronted by authorities. "I have questions for the secretary!"

Video of the incident shows the senator struggling with multiple Secret Service agents before being shoved out of the room and dragged away, before uniformed FBI agents placed him on the ground and arrested him.

Noem, who was speaking about immigration and the protests in LA, continued addressing reporters and law enforcement officers while the senator was ejected.

Padilla's removal prompted immediate condemnation and an angry backlash on Capitol Hill, where fellow Democratic members of Congress called the arrest a "sickening disgrace" and an "affront to democracy".

LA Mayor Karen Bass called it "absolutely abhorrent and outrageous", adding that the Trump administration's "violent attacks on our city must end".

Some Republicans also condemned the incident. "It's horrible," Senator Lisa Murkowski told reporters. "It is shocking at every level. It's not the America I know."

In a video posted to social media later in the day, Padilla said he "couldn't accept the rhetoric anymore" during the news conference and so tried to interject with a question.

"I'm OK," he said. "But if they can do that to me, a United States senator... what are they doing to a lot of folks out there when the cameras are not on?"

"What we've seen here should not be normalised," he added.

Kristi Noem said she met with Padilla for 15 minutes afterwards, saying while they "probably disagree on 90% of the topics", the pair would continue to talk.

"I wish he would've acted that way in the beginning rather than creating a scene," she said in a social media post.

The Trump administration accused Padilla of "disrespectful political theatre".

In a statement, the Department of Homeland Security said he lunged at Secretary Noem. That was disputed by the senator's office and fellow Democrats.

The department said the senator was told to back away and did not comply with officers' commands, adding that the Secret Service "thought he was an attacker".

Padilla told reporters that he was already in the federal building for a previously scheduled meeting. He said he stopped by Noem's news briefing because he and his colleagues have received "little to no information in response" to several immigration-related queries.

Padilla, the son of Mexican immigrants, is the most senior Democrat on the Senate's Border Security and Immigration subcommittee.

"I came to the press conference to hear what she had to say, to see if I could learn any new additional information," he said.

He urged Americans across the country to "continue peacefully protesting" the Trump administration and its policies.

California's Governor Gavin Newsom called on Republican congressional leadership to condemn the detaining of Padilla.

"If they can handcuff a US Senator for asking a question, imagine what they will do to you," Newsom wrote on social media.

But the White House accused the California senator of storming the press conference.

"Padilla didn't want answers; he wanted attention," Abigail Jackson, White House spokesperson said. "Padilla embarrassed himself and his constituents with this immature, theatre-kid stunt – but it's telling that Democrats are more riled up about Padilla than they are about the violent riots and assaults on law enforcement in LA."