The roof of a porch on Semple Street collapsed during a St. Patrick’s Day celebration on Friday at around 5:30 p.m., injuring over a dozen people.

Video taken at the party shows at least 20 people sitting and standing on the roof when it buckled, falling onto more partygoers.

According to City Public Information Officer Emily Bourne, Pittsburgh EMS transported 16 people from the scene, with 13 in stable condition and three in serious, but stable condition. Bourne said most people were transported for concussions and minor arm and leg injuries, with one person believed to have a leg fracture.

Bourne added that another dozen people were treated on-scene for minor abrasions. City Police, Fire and EMS responded to the incident along with Pitt Police.

At 6:03 p.m., Pitt Police announced the 300 block of Semple Street would be closed until further notice. At least three ambulances and one fire engine responded to the scene.

Pitt Police and City Police responded to the scene and people who were injured were transported for care, according to a tweet sent by Pitt Police at 7:21 p.m. Pitt Police added it will work with City agencies to investigate the roof collapse.

“As a reminder, it is never safe to be on rooftops,” Pitt Police tweeted.

This story is developing and will be updated.