Five people have been injured in a suspected explosion at a Tube station.
Witnesses described smelling "burning rubber" at the entrance to Southgate underground station in Enfield.
Police were called to reports of people running from a minor explosion, thought to be caused by a battery short circuit, just after 19:00 BST.
Paramedics treated five people at the scene and took two to hospital. British Transport Police said the incident was not thought to be terror-related.
'Like burning rubber'
Haluk Ozkan was about to get on a bus outside the station when he smelt something burning.
The finance worker, 26, who was with his partner at the time, said: "We were just outside the exit. We could smell a burning smell, like burning rubber."
"We thought the bus engine had over-heated," he added.
"We then saw people rushing to get out of the station. Not necessarily running or panicking, but moving quickly.
"Then my partner saw a station staff member pointing a fire extinguisher at something and heard it go off, but we didn't see what it was directed at."
A London Ambulance spokesperson said: "We were called today at 19:02 BST to an incident at Station Parade, N14.
"We have treated three patients at the scene for minor injuries and have taken two people to hospital."
Specialist officers said the cause of the explosion appeared to be a battery short circuit.
Enquires are ongoing to establish the "full facts", a Met spokesman added.
Scotland Yard said officers remained at the scene along with colleagues from British Transport Police, London Fire Brigade and the London Ambulance Service.
Cordons are in place and the station is closed.
London Mayor Sadiq Khan
I am in touch with senior Met Police about the reported minor explosion at Southgate Tube station. They are investigating. Please avoid the area and follow @metpoliceuk for updates. https://t.co/PtqyfUXorY— Mayor of London (@MayorofLondon) June 19, 2018