Detectives from the Metropolitan Police’s Counter Terrorism Command are now investigating the incident at Leytonstone Underground station.
Police were called at 19:06hrs on Saturday, 5 December, to reports of a number of people stabbed at the station. The male suspect was reportedly threatening other people with a knife.
Video footage has emergenced from the scene.
Met officers attended the scene. A man was arrested at 19:14hrs and taken to an east London police station where he remains in custody. A TASER was discharged by one of the Met officers.
One man has sustained serious knife injuries; these are not believed at this stage to be life-threatening. Two other people have sustained minor injuries.
Commander Richard Walton, who leads the Met’s Counter Terrorism Command, said:
“We are treating this as a terrorist incident. I would urge the public to remain calm, but alert and vigilant.
“The threat from terrorism remains at severe, which means that a terrorist attack is highly likely.
“I would appeal to anyone who was in the vicinity of Leytonstone underground station earlier this evening at around 7pm who saw anything suspicious to call the anti-terror hotline on 0800 789 321.
“Anyone who may have captured video or photographic footage of the incident is also urged to make contact with the Counter Terrorism Command via the Anti Terror hotline”.