The police have not yet revealed the cause of the explosion that led to mass panic and a stampede at the District Line station Parsons Green.
Witnesses said victims suffered facial injuries after a white cannister exploded, with one saying a “fireball flew down the carriage”.
An image shared on social media shows a white bucket containing something black burning inside a London Underground tube carriage.
Wires can be seen coming out of the bucket in a Lidl bag.
Armed police rushed to the Tube station where a woman was seem being carried off on a stretcher with her legs covered in a foil blanket.
“We are aware of an incident at ParsonsGreen tube station. Officers are in attendance,” London police said on Twitter.
Police, paramedics and firefighters were called to the station on the District Line at about 8.20am.
“We are aware of an incident at ParsonsGreen tube station. Officers are in attendance,” London police said on Twitter.
Transport for London said on Twitter that there was no service between Earls Court and Wimbledon on the District Line which runs through Parsons Green.