Beverly Hills is facing criticism after officers arrested 28 people during a peaceful protest against police violence overnight, two weeks after imposing an unusual ordinance banning demonstrations in residential areas that “disrupted the tranquility.”

The latest protest, which began about 7:30 p.m. Friday and drew about 75 people, was the third demonstration in Beverly Hills organized by the Black Future Project, but the first that resulted in arrests, said organizer Austin Tharpe, 29.

“We’re protesting for Black lives,” he said. “Specifically in Beverly Hills, because of the privilege and the whole makeup of the community, we felt like our voices needed to be heard over there.”

He said that after protesters marched for several hours, police deployed a long-range acoustic device, also known as a sonic cannon, and declared the demonstration an unlawful assembly just before midnight.

“We put the signs on the ground,” he said. “We turned around and faced away from the cops with our knees on the ground and our hands behind our head.”

He said that officers continued to yell out orders to disperse.

A total of 28 people were taken into custody, most on suspicion of unlawful assembly, though one person faced an attempted arson charge after allegedly trying to set fire to a large American flag that was attached to a building, said Sgt. Thomas West of the Beverly Hills Police Department.

That person was associated with the protest but not the Black Future Project, Tharpe said.

The Police Department planned to hold the protesters under what’s called a misdemeanor non-release, which would have required that they post $5,000 bail to get out, West said.

Later in the day, citing a directive from command staff, the department reversed course and said the protesters would be cited and released on their own recognizance, provided that they did not have outstanding warrants.

The demonstrators remained in custody late Saturday afternoon, prompting concern from activists who said they should have been cited and released more quickly.

Many protesters still had not been released by 7 p.m. Saturday. In a statement, a city spokesman said that the Police Department had “added additional staff to facilitate the process.”

Asked to comment, Mayor Lester Friedman released a statement saying that protesters were given multiple warnings.

“Last night’s protest in a residential area,” he said, “was a violation of the City’s Civil Emergency Order.”

The order, which took effect June 13, states that no more than 10 people are allowed to gather for an assembly in a residential area from 9 p.m. to 8 a.m.