At least four people were reportedly taken to hospital with injuries after an explosion at the 'Perekrestok' supermarket in the Gigant Hall leisure centre in St. Petersburg, Wednesday. Footage filmed by an eyewitness shows the area cordoned off, with police and emergency vehicles outside. According to reports, the explosion took place at around 18.30 local time. The Russian investigative... Еще committee has said that four people were hospitalised, and that one of victims suffered serious injuries. Nearly 50 officers of the emergency services are operating at the scene. Six other people also sustained injuries, according to reports. The cause of the explosion is under investigation. According to reports, it is being treated as a potential mass homicide attempt.