London Underground passengers have been injured following an explosion on a District Line train in south-west London.
Police and paramedics were called at 08:20 BST (07:20 GMT) on Friday to Parsons Green station in Fulham.
Pictures show a white bucket on fire inside a supermarket bag, but does not appear to show extensive damage to the inside of the Tube train carriage.
Witnesses described seeing at least one passenger with facial injuries.
Others have spoken of “panic” as alarmed passengers left the train at Parsons Green station.
Passenger Chris Wildish saw a bucket in a supermarket bag with “low-level flames coming out of it” by the door of the rear carriage.
One witness, called Luke, told 5 Live there was “a sort of loud explosion”.
“It happened just as we were pulling up to the Tube station so everyone just sort of piled out of the Tube and there was a distinct smell of burning,” he said.
“I certainly saw some burning injuries,” he said, but added that “everyone behaved in the right manner as such, everyone got off as quickly as they can and you know supported everyone”.
Emma, who was at Parsons Green station, said: “We were running down the stairs like… it felt like for our lives…
“And I went down the stairs and after a while people were just piling on top of each other, because people were falling over trying to run so quickly.
“And there were two ladies underneath me and a little boy to my right, his head had been smacked into the concrete.”
BBC London presenter Riz Lateef, who was at Parsons Green on her way in to work, said: “There was panic as people rushed from the train, hearing what appeared to be an explosion”
“People were left with cuts and grazes from trying to flee the scene. There was lots of panic.”
It is now being treated as a terrorist incident. Police are currently looking for an armed man said to be on the run with a knife.
Witnesses also said that bomb disposal units were deactivating a second bomb, however this has not been confirmed.