Several people were hurt, including an off-duty police officer, in what people called a "flash mob" attack in Center City on Saturday night.

According to police, a smaller group of juveniles broke off from a large crowd and began attacking people in the area of 16th and Walnut streets around 6 p.m. Saturday night. Six people were injured.

Officials say one of the victims was a 55-year-old police officer, who was off-duty at the time. The officer, who has not yet been identified, was punched repeatedly while trying to grab one of several teens kicking two individuals and suffered a possible fracture to his right orbital bone. His wife was also assaulted and punched in the face after throwing water on the assailants in an attempt to stop their attack.

"We looked and we saw people who had obviously been beaten up," an unnamed witness told NBC10. "They were bleeding from their heads. We saw at least three people that were like that."

Police did not respond to the Inquirer's requests for information last night. Witnesses said a patron was thrown out of Coda nightclub and scuffled with an off-duty officer.

Police say two teens, both 16 years old, were arrested, and investigators are looking for surveillance footage to help gather evidence in order to identify more potential suspects.

Two weeks ago, four teens were arrested in a similar "flash mob" incident near Temple University's main campus in North Philadelphia. That attack, which included as many as 150 juveniles, left at least one student hospitalized in wide-ranging violence that police said included rocks being thrown at cars and a police horse being punched.

This is a breaking news report. Check back for updates.