There has reportedly been an explosion at Parsons Green station.
The incident happened on a District Line train on Friday morning during rush hour, and there are reports of a stampede and several injured.
Some of the wounded are claimed to have injuries extending as far as facial burns.
Pictures on social media show the authorities working at the station, as well as an image of the suspected cause of the explosion, a white cannister.
The authorities are currently working on the scene, and Transport for London has advised commuters to use alternative routes as it investigates the incident.
The District Line in the west of the capital between Wimbledon and Earl's Court has been shut down as the work carries on.
The authorities have said it is being treated as a terror incident.
More on this to follow.