London: Flames engulfed one carriage and raced along a train on a west London route to Parsons Green, forcing passengers to trample others as they rushed for an exit, an eyewitness told Reuters.
The man said people were trampled on when they fled the train after hearing a whoosh and seeing flames race towards them. He said he did not hear a bang after police rushed to an incident at the station at Parsons Green.
"I just heard a kind of whoosh. I looked up and saw the whole carriage engulfed in flames making its way towards me," he told Reuters, adding that the train was packed with people.
The city's District Line has been affected at Parsons Green station and several people are believed to have been hurt as a result of a large white plastic bucket in a supermarket plastic bag exploding in one of the carriages.
"We are aware of reports on social media RE #ParsonsGreen. We will release facts when we can - our info must be accurate," the Metropolitan Police said on Twitter.
While the nature of the explosion is not yet known, Met Police bomb squads and fire crews have been rushed to the station along with ambulances.
Eyewitnesses from shops outside the station have reported seeing people with facial injuries. Many have been told to stay in lockdown until the police gives an all clear.