Emergency services are at the scene of a reported explosion on a District Line Underground train in south-west London.
A picture on social media showed a white bucket inside a supermarket bag, but does not appear to show extensive damage in the carriage.
National news sources say 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 at around 08:20 BST (07:20 GMT) on Friday morning.
London Ambulance Service says it has sent a hazardous area response team to the scene.
According to BBC reports there was panic as people rushed from the train, hearing what appeared to be an explosion.
Natasha Wills, assistant director of operations at London Ambulance Service, said: “We were called at 8:20 to reports of an incident at Parsons Green underground station.
“We have sent multiple resources to the scene including single responders in cars, ambulance crews, incident response officers and our hazardous area response team, with the first of our medics arriving in under five minutes.
“Our initial priority is to assess the level and nature of injuries.”
More information will follow when we have it.