More than 20 people were injured when escalator in a Rome metro station, packed with football fans, suddenly accelerated before collapsing, causing a mass pile-up.

Videos of the incident on social media showed people being thrown against one another as they scrambled to escape by jumping onto a parallel escalator. According to The Guardian, many of those injured due to the shattered stairs were fans of the CSKA Moscow team.

Rome’s transportation company ATAC and Rome’s public prosecutor opened investigations into the cause of the accident. However, Rome’s mayor, Virginia Raggi, said, “From some testimonies, it looks like some fans were jumping and dancing on the escalator.” She also expressed sympathy for those injured.