Passengers reported seeing a device on the train at the Parsons Green station in south-west London and hearing a bang during the morning rush hour, reports the Guardian.
The Metropolitan and British Transport police forces rushed to the scene. The exact number of injured was not disclosed.
Pictures on social media showed a white bucket on fire inside a supermarket bag but did not appear to show extensive damage to the inside of the train carriage, the BBC reported.
Witnesses described seeing at least one passenger with facial injuries. Others spoke of panic as stunned passengers trooped out of the train.
A BBC London Correspondent who was at Parsons Green on her way 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."
Train services between Earl's Court and Wimbledon on the District Line were immediately suspended.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)