Updated | London attack: Explosion on Parsons Green tube being treated as 'terrorist incident'

The explosion of a crude device occured at 8:20am on a crowded District line train as it left the Parsons Green station in Southwest London. The explosion injured commuters, sowed panic and disrupted service, with the tube service being partially suspended, according to Transport for London spokeswoman.

The Metropolitan and British Transport police forces, including armed officers were at the scene, alongside the London ambulance service. 

"This was a detonation of an improvised explosive device", said Assistant Commissioner Mark Rowley, a top counter-terrorism official, said at a news conference. He went on to urge anyone who saw what had happened, or had taken photos or videos of the bombing, to come forward.

The Maltese government said it has not received any reports of any Maltese citizens who may have been injured or caught in this attack.

Image of the apparent device on the train Parsons Green Tube (Photo: Twitter)

“In the event that any Maltese have relatives in the area or may wish to report a missing relative or loved one, kindly contact the Malta High Commission on +44 (0) 20 72924800 or +44 (0) 7836 503990,” the Ministry for Foreign Affairs said.

At least 18 people were taken to hospitals, several of them apparently injured as panicked commuters fled. None had life-threatening injuries and hospital officials described the victims as the "walking wounded".

Several people are said to have suffered from facial burns, after the reported blast in a bucket towards the rear of the District Line train. Others are said to have been trampled in the rush to escape.

One witness reported seeing "a flash and a bang" in a bag holding the container, which is said to have had wires coming from it, on the packed rush-hour carriage.

Media technology consultant Richard Aylmer-Hall, 53, was sitting on the District line train bound for central London at about 8.20am, when panic struck.

“Suddenly there was panic, lots of people shouting, screaming, lots of screaming,” he said. “There was a woman on the platform who said she had seen a bag, a flash and a bang, so obviously something had gone off.”

He added: “I saw crying women, there was lots of shouting and screaming, there was a bit of a crush on the stairs going down to the streets. Some people got pushed over and trampled on. I saw two women being treated by ambulance crews.”

A reporter from London’s Metro newspaper reported seeing people with facial burns.