SANTA MONICA (CBSLA) – Los Angeles County will join the cities of Santa Monica and Beverly Hills – both of which experienced the brunt of the looting and violence over the weekend during the George Floyd demonstrations – in imposing another round of curfews Monday.

Police watch as tear gas is deployed during demonstrations in the aftermath of George Floyd’s death on May 31, 2020 in Santa Monica, Calif. (Getty Images)

READ MORE: Norms Diner Anniversary Celebration Includes 72-Cent Breakfast Special, Hotcake Doughnut From Randy's Donuts

Initially L.A. County announced a countywide curfew for incorporated and unincorporated areas that will run from 6 p.m. Monday to 6 a.m. Tuesday. That was later moved up to 5 p.m. Monday.

Santa Monica and Beverly Hills reported that they will impose their own more stringent citywide curfews that get underway at 1 p.m. Monday for their business districts and 4 p.m. citywide. The Beverly Hills curfew extends through 5:30 a.m. Tuesday.

Beverly Hills was hard hit by looting and fires in its Fairfax District on Saturday, while Santa Monica’s Third Street Promenade was also devastated by looting and fires Sunday. A Vons grocery store in the 700 block of Broadway was completely ransacked as well.

In a news conference Monday morning, Santa Monica Police Chief Cynthia Renaud said more than 400 people were arrested Sunday on various charges, including burglary, looting and assault with a deadly weapon. She said 95% of the suspects were not residents of Santa Monica. She called the looters “opportunists” who track where protests will be taking place and look to take advantage of the fact that law enforcement resources will be stretched thin.

“So what we can glean from intelligence online is that there are opportunists who are tracking where peaceful protests are occurring, and they are then going to that city, knowing that resources will be tied up in ensuring First Amendment rights to free speech,” Renaud said. “They take advantage of that. And they loot and they perform criminal activity.”

About 100 National Guard troops were finally brought in to Santa Monica Sunday night to help get the crowds to disperse, Renaud said. The troops remained in the city Monday to patrol and provide security. She noted that they are a peacekeeping force and do not enforce laws.

There were no serious injuries to officers or protesters. In total, nine fires were set.

READ MORE: Gunman In Parkland School Massacre Pleads Guilty To Murder

Santa Monica police, firefighters and city crews and some good Samaritans were on the street early Monday morning to begin the cleanup process and efforts to restore the damaged businesses. Several of them told CBSLA that they had been part of yesterday’s peaceful protest.

“It’s heartwarming that you see people out here with brooms, they don’t know anybody in these buildings — they don’t know who I am — hopefully we can rebuild and come back strong,” Engineer Frank Lopez said.

The city was asking anyone who wanted to help in the cleanup to bring their own face- coverings, work gloves, brooms dustpans and trash bags.

“Much was lost on Sunday, including property and innocence,” Santa Monica Mayor Kevin McKeown said in a statement Monday. “As mayor, I’m grateful that we did not lose any lives.  Our public safety officers showed professional restraint and resolve under the most difficult of circumstances.”

About 1,000 National Guard personnel were deployed Saturday night after Gov. Gavin Newsom declared a state of emergency for all of Los Angeles County. They were deploying areas hard hit by the violence and looting, including downtown L.A., Long Beach, Santa Monica and Beverly Hills.

Young men sit in handcuffs under arrest on May 31, 2020 Santa Monica. (Getty Images)

L.A. Mayor Eric Garcetti said he hoped the deployment of the guard to L.A. will be a “very short visit,” but there is no fixed timeline. The last time the National Guard was deployed to L.A. was during the Rodney King riots in 1992.

L.A. County Board of Supervisors Chair Kathryn Barger announced Sunday that she has proclaimed a state of emergency as well, which will facilitate interagency response coordination and mutual aid, accelerate the procurement of vital supplies and enable future state and federal reimbursement of costs incurred by the county.

MORE NEWS: Huntington Beach Officially Calls For Offshore Oil Drilling Ban

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)