US Marines carry out first known detention of civilian in Los Angeles, video shows

Los Angeles/Washington: Marines deployed to Los Angeles temporarily detained a civilian on Friday, the US military confirmed after being presented with Reuters images, in the first known detention by active-duty troops deployed there by President Donald Trump.

The incident took place at the Wilshire Federal Building in Los Angeles where Marines took charge of the mission to protect the building earlier on Friday, in a rare domestic use of US troops after days of protests over immigration raids.

Reuters images showed Marines apprehending the man, restraining his hands with zip ties and then handing him over to civilians from the Department of Homeland Security.

Asked about the incident, the US military's Northern Command spokesperson said active duty forces "may temporarily detain an individual in specific circumstances."

"Any temporary detention ends immediately when the individual(s) can be safely transferred to the custody of appropriate civilian law enforcement personnel," a spokesperson said.

Speaking to reporters after he was released, the civilian identified himself as Marcos Leao, 27. Leao said he was an Army veteran on his way to an office of the Department of Veterans Affairs when he crossed a yellow tape boundary and was asked to stop.

Leao, who gained his US citizenship through military service, said he was treated "very fairly."

"They're just doing their job," said Leao, who is of Angolan and Portuguese descent.

The 200 Marines and more than 2,000 National Guard now deployed to Los Angeles are tasked with protecting federal property and federal personnel. They will be joined by an additional 500 Marines and 2,000 more National Guard soldiers.

This means that they will accompany ICE agents on raids, officials have said.

The troops are authorized to detain people who pose a threat to federal personnel or property, but only until police can arrest them. Military officials are not allowed to carry out arrests themselves.

The Posse Comitatus Act generally forbids the US military, including the National Guard, from taking part in civilian law enforcement.

Trump could take a more far-reaching step by invoking the Insurrection Act, which would allow troops to directly participate in civilian law enforcement.