LA police order US immigration protesters to go home

Police have declared all of downtown Los Angeles to be an unlawful assembly area, ordering protesters to go home after a third day of violence hit demonstrations against President Donald Trump's immigration policy.

National Guard troops - deployed by Trump at the weekend to help quell the protests in a move that California Governor Gavin Newsom called unlawful - guarded federal government buildings on Sunday.

The unrest in Los Angeles has become a major flashpoint in Trump's signature effort to clamp down on illegal immigration.

The Republican president has pledged to deport record numbers of people who are in the country illegally and to lock down the US-Mexico border, setting the border enforcement agency ICE a daily goal of arresting at least 3000 migrants.

California state and local officials, mainly Democrats, accuse Trump of inflaming initially small-scale protests by mounting a federal response.

He calls the protesters insurrectionists.

Several self-driving cars from Alphabet's Waymo were set ablaze on a downtown street on Sunday evening.

Los Angeles police said some protesters had thrown concrete projectiles, bottles and other items at police.

Police declared several rallies to be unlawful assemblies and later extended that to include the whole downtown area.

Demonstrators shouted "Shame on you!" at police and some appeared to throw objects, video images showed.

City Police Chief Jim McDonnell told a media briefing on Sunday evening that people had a right to protest peacefully but the violence he had seen by some was "disgusting" and the protests were getting out of control.

Police said they had arrested 10 people on Sunday and 29 the previous night, adding that arrests were continuing.

California Governor Newsom, a Democrat, said he requested the Trump administration to withdraw its order to deploy 2000 National Guard troops in Los Angeles County, calling it unlawful.

Newsom said in an interview with MSNBC he planned to sue the administration over the deployment, adding that Trump "has created the conditions" around the protests.

He accused the president of trying to manufacture a crisis and of violating California's state sovereignty.

Asked if the National Guard was needed, the police chief, McDonnell, said police would not "go to that right away" but added: "Looking at the violence tonight, I think we've got to make a reassessment."

In a social media post, Trump called on McDonnell to do so.

"He should, right now!!!" Trump added. "Don't let these thugs get away with this. Make America great again!!!"

The White House disputed Newsom's characterisation, saying in a statement, "everyone saw the chaos, violence and lawlessness".

Earlier on Sunday, about a dozen National Guard members, along with Department of Homeland Security personnel, pushed back a group of demonstrators outside a federal building in downtown Los Angeles, video showed.

The US Northern Command said 300 members of the California National Guard had been deployed to three sites in Los Angeles.

Homeland Security Secretary Kristi Noem told CBS the National Guard would provide safety around buildings to people engaged in peaceful protest and to law enforcement.

In a social media post on Sunday, Trump called the demonstrators "violent, insurrectionist mobs" and said he was directing his cabinet officers "to take all such action necessary" to stop what he called riots.

Despite Trump's language, he has not invoked the Insurrection Act, an 1807 law that empowers a president to deploy the US military to suppress events such as civil disorder.

Defense Secretary Pete Hegseth said on Saturday the Pentagon was prepared to mobilise active-duty troops "if violence continues" in Los Angeles, saying Marines at nearby Camp Pendleton were on high alert.

Los Angeles Mayor Karen Bass blamed the Trump administration for inciting tension by sending in the National Guard and condemned protesters who became violent.

Vanessa Cardenas, head of the immigration advocacy group America's Voice, accused the Trump administration of "trumping up an excuse to abuse power, and deliberately stoke and force confrontations around immigration".