PITTSBURGH — The mayor is strongly condemning tactics used in the arrest of a protester during a march over the weekend that drew condemnation from the American Civil Liberties Union and others, and says he won’t tolerate such actions in the future.

“It is hard to find the words for how livid I was after seeing the online videos of the disturbing arrest at Saturday’s protest,” Mayor Bill Peduto said Monday. “As mayor, I will never tolerate these tactics being used at peaceful protests again.”

On Sunday, Peduto said he had “serious concerns” after plainclothes officers arrested a protester at about 5 p.m. Saturday in Oakland and placed him in an unmarked, white van. About 150 protesters marched to his house and demonstrated there.

Public Safety officials said they were trying to protect the public, saying the protester refused to work with police, blocked intersections needed for hospital access and they feared he might direct cars into other vehicles or pedestrians. Officials said they opted for a “low visibility” arrest to avoid inflaming the situation.