A group of teenagers allegedly looted a Walgreens in downtown Philadelphia Thursday evening, according to video footage of the incident.

The video showed dozens of teens running through the streets on Philadelphia’s South Street Thursday, but things began to get violent when a group of 60 teens descended on Walgreens.

CBS Philly reported that as the crowd moved west on South Street and violence broke out around 10 p.m., authorities advised businesses and residents to lock their doors.

Once the mob of teens got to the Walgreens on 18th and South Streets Thursday evening, at least one of the teens was responsible for allegedly hitting a Walgreens clerk in the head with a glass bottle when he tried to intervene.

“About 60 juveniles walked into the establishment and began removing things from the shelves, destroying property inside the store. The cashier attempted to intervene and some heavy item – I believe it was a bottle – was thrown at him, striking him in the head,” Captain Sekou Kinebrew of the Philadelphia Police Department told WPVI.

The injured clerk suffered cuts and bruises but was treated and released.

The Walgreens itself suffered thousands of dollars in damage, police say.

“Between the things that they stole and the property damaged inside, it’s between $6,000 and $7,000 in damage,” said Kinebrew.

Police have not made any arrests and are continuing to investigate the incident.