British police have declared a terrorist incident after a blast sent a "fireball" and a "wall of flame" through a packed London Underground train.
Assistant Commissioner Mark Rowley said the explosion was caused by the detonation of an improvised explosive device.
Mr Rowley said it is understood that "most" of the 18 people injured in the blast were suffering from "flash burns".
Officers from the Metropolitan Police's counter-terrorism command have launched an investigation following the explosion in west London during rush hour.
The force said police were called at approximately 8.20am to Parsons Green Underground Station "following reports of a fire on the train".
The Met said Deputy Assistant Commissioner Neil Basu, the national coordinator for counter-terrorism policing, "has declared it a terrorist incident", adding: "At present we are aware of a number of people who have suffered injuries."
British Prime Minister Theresa May is to chair a meeting of the government's Cobra emergencies committee this afternoon to discuss the incident.
The PM said: "My thoughts are with those injured at Parsons Green and the emergency services who, once again, are responding swiftly and bravely to a suspected terrorist incident."
Commuters fled in terror after the blast and witnesses reported seeing several people hurt and "covered in blood" after a "flash and a bang" on the District Line Tube.
Emergency services including armed police rushed to the scene and cordoned off the station.
Pictures posted on social media appeared to show wires protruding from a flaming bucket inside a plastic carrier bag on the floor of a carriage.
The Met said: "It is too early to confirm the cause of the fire, which will be subject to the investigation that is now under way by the Met's Counter Terrorism Command."
Media technology consultant Richard Aylmer-Hall, 53, was sitting on the District Line train bound for central London when panic unfolded at around 8.20am.
He said he saw several people injured, having apparently been trampled as they tried to escape.
He told the Press Association: "I was blissfully reading my paper and listening to a podcast and suddenly the whole world charged past me down the platform, down the Tube."
Sylvain Pennec, a software developer from Southfields, near Wimbledon, was around 10m from the source of the explosion when fire filled the carriage.
"I heard a boom and when I looked there were flames all around," he said.
A major incident has been declared at St Mary's Hospital in Paddington in response to the Parsons Green explosion.
The Metropolitan Police urged anyone with photographs from the scene to upload them to www.ukpoliceimageappeal.co.uk to aid the investigation.
Courtesy: https://www.rte.ie/ published on Sept 15, 2017