Protests live updates: Marines make 1st temporary detention in LA

More than 100 people were arrested on Monday night in Los Angeles, as "fringe groups" continued late-night protests, City of Los Angeles Mayor Karen Bass said.

"What we're seeing downtown is just horrible, but you know that the majority of people that attended the protest this afternoon were peaceful," Bass told ABC News' KABC station in a phone interview late Monday night.

She said the more-violent protesting and vandalism were happening "late at night," adding that she assumed violent protests weren't being led by people supporting immigrants, but rather by "fringe groups."

"It's my understanding that over 100 people have been arrested tonight, the majority of them for unlawful assembly," she said.

She said each of those who were arrested would be "evaluated," including checking to see whether they have active warrants.

"But, again, this has nothing to do with the protests that happened earlier this afternoon," Bass said. "That was a protest -- fighting for the rights of immigrants and calling for the raids to stop."

The Federal Bureau of Investigation has identified a man who is wanted for throwing rocks at police and law enforcement vehicles during the protest in Paramount, California, on Saturday.

The suspect has been identified as 40-year-old Elpidio Reyna, from nearby Compton, and is wanted for assault on a federal officer, according to the FBI

The FBI is offering a reward of up to $50,000 for information about the suspect, leading to his arrest and conviction.

The incident happened at approximately 3:30 p.m. on Saturday, according to the FBI, when the suspect threw rocks at law enforcement vehicles on Alondra Boulevard in Paramount, injuring a federal officer and damaging government vehicles.

As the immigration protests in Los Angeles continue, demonstrations were also seen in New York City, Austin, Texas, and just south of L.A. in Santa Ana, California.

The number of National Guard troops on the ground in the Los Angeles area has risen from 300 to 1,700, the Defense Department said in an update Monday evening.

The guardsmen are from the 79th Infantry Brigade Combat Team, a California National Guard unit. They are operating under Task Force 51, which also includes 700 Marines, to protect federal personnel and property, U.S. NORTHCOM said in a statement.

President Donald Trump's memo over the weekend authorized a deployment of 2,000 National Guardsmen amid unrest during protests over immigration enforcement in the LA area.

California Gov. Gavin Newsom said Monday he had been informed Trump planned to deploy an additional 2,000 National Guard troops.