A police officer has been suspended from active duty, after a clip of a violent arrest at Pittsburgh Pride surfaced online.

The clip showed police officer Souroth Chatterji grabbing Ariel Lawther, who was wearing rainbow clothing, by the head and punching her, before restraining her in front of the crowd.

The incident took place at Pittsburgh pride on Sunday afternoon, and the officer has been placed on desk duty for a month while the arrest is investigated.

According to Chatterji’s report, Lawther had been engaged in a conflict with Eric Moure, who is believed to have been protesting the pride event.

Chatterji claims that Lawther “struck him repeatedly” before the arrest shown in the clip, adding: “I punched Lawther in the left abdomen several times to distract her enough so I could handcuff her”.

His report also claimed he had spoken to Lawther half an hour before the arrest, asking her not to be “physically offensive” towards the demonstrators.

Ariel Lawther, of Harmony, was charged with aggravated assault against the officer, and simple assault against the other man.

Pittsburgh mayor Bill Peduto said the city “won’t look the other way when incidents like this happen”, and confirmed the officer will remain on restricted duty during the internal investigation.

The Delta Foundation, which supports the pride, said: “We are pleased that Mayor Bill Peduto has issued a full investigation into the matter that occurred between the City of Pittsburgh police officer and Ariel Lawther.

“It is our understanding that Ms. Lawther has been released from jail and we are currently in the process of reaching out to her to see if there’s anything the Delta Foundation can do for her.

“In the meantime, we have contacted U.S. Attorney General David Hickton’s office to also inform them of the incident and launch a potential hate crime investigation.”