Five people have been injured after an explosion at a London underground station, which officials said they believed was caused by a battery short circuit. Officers were called to reports of people running at Southgate Tube station shortly after 7pm on Tuesday amid what they described as a "minor explosion". London Ambulance Service said two people had been taken to hospital and three others were treated at the scene in north London for minor injuries. The incident is not believed to be terror-related, British Transport Police (BTP) said. The Metropolitan Police said: "The scene has been examined by specialist officers. "It appears at this stage that the cause of the explosion was a battery short circuit. The Met Police and BTP are working together to establish the full facts." Passengers described scenes of panic. James Ayton, 34, from Southgate, was on the escalator when he saw a "quick burst" of flames at the top. He said the flames were "six foot plus" and everyone "legged it". Mr Ayton said: "It wasn't a bang. It was like a very rapid whooshing sound." He said the escalator was "packed", adding: "The Tube had just unloaded. The escalator was full." Mr Ayton said: "A few people got trampled on on the escalator. There was screaming. "An old woman got trampled on. I had to carry a woman up the stairs. I think she was in shock to be honest. She couldn't walk, shaking." He said he saw a Tube worker pick something up that was on fire and extinguish it but he added: "I think that was secondary rather than the cause." A spokeswoman for London Ambulance said: "We sent multiple resources to the scene, including a number of ambulance crews, our hazardous area response team, a medic in a fast response car, an advanced paramedic and an incident response officer. "We have treated three patients at the scene for minor injuries and have taken two people to hospital." TSSA (Transport Salaried Staffs' Association) general secretary Manuel Cortes said: "Our thoughts are with those caught up in this incident and their loved ones." Police continued to offer updates as they later dealt with a "suspicious package", with sniffer dogs brought in to sear within a cordoned off area outside on the street. In a tweet, the Metropolitan Police said: "Met officers are dealing with a suspicious package at #Southgate tube station. Cordons are in place and officers remain at the scene. We will update with more info as we get it." They added later: "Officers remain at #Southgate tube station. Enquires are ongoing to establish the cause of a reported minor explosion at 19:03 hours. We are not aware of any serious injury." There were reports on social media that residents living nearby were being asked to evacuate buildings as officers continue to assess the level of threat. City worker Darren Yarlett, 36, told the Evening Standard: "The police moved us on, but they said there was an explosion in the station. "There must be around 50 or 60 police, an ambulance, fire arms and dog units."