Terror strikes the Tube: What we know so far about the Parsons Green bucket bomb

Police are investigating a suspected terror attack at Parsons Green in west London after an explosion on a District Line tube train shortly before 9am, in which a number of people were injured.

Eye-witnesses reported hearing loud bangs coming from a bucket which was located towards the rear of the train.

Photographs taken by commuters show a suspected device in a large plastic bucket wrapped in a Lidl supermarket carrier bag.

The bucket also had a number of wires protruding from the top, and security sources who saw pictures, said it looked to be a homemade explosive device which had not gone off, although that is yet to be confirmed.

Several people were reportedly injured when a fire ball spewed from the device causing burns, and a number of other people were reportedly injured in the ensuing stampede.

St Mary's Hospital in Paddington said they had declared a major incident in response.

Armed police were on the scene and were being supported by officers from British Transport Police.

In a statement shortly before 10.30am, Scotland Yard confirmed they were treating the incident as a suspected terror attack.

The statement said: "Police were called at approximately 08:20hrs on Friday, 15 September to Parsons Green Underground Station following reports of a fire on the train.

"Deputy Assistant Commissioner Neil Basu, the senior national coordinator for CT policing, has declared it a terrorist incident.

"Officers from the Metropolitan Police Service and British Transport Police attended the scene, along with colleagues from the London Fire Brigade and London Ambulance Service.

"At present we are aware of a number of people who have suffered injuries.

"It is too early to confirm the cause of the fire, which will be subject to the investigation that is now underway by the Met's Counter Terrorism Command.

"The station remains cordoned off and we are advising people to avoid the area."

One passenger, named only as Lucas, told BBC 5 live: "I heard a really loud explosion - when I looked back there appeared to be a bag but I don't know if it's associated with it.

"I saw people with minor injuries, burnings to the face, arms, legs, multiple casualties in that way. People were helping each other."

Another witness, Sham, said he saw a man with blood all over his face.

"There were loads of people crying and shaking," he told 5 live. There were a lot of people limping and covered in blood.

"One guy I saw, his face was covered in blood - I've never seen anything like it."

Pictures circulating on social media showed passengers with various injuries, including serious burns.

BBC News presenter Sophie Raworth, who was at the scene, said she saw a woman on a stretcher with burns to her face and legs.

"I spoke to a woman, Laura Bishop, who said she was standing there and all of a sudden heard a bang - and saw a wall of flames, flames in the carriage," she said.

"She saw people who had burns on their hair, burns on their head and the doors opened immediately."

Ms Raworth added: "I have just seen a woman who was just stretchered off here and clearly her legs are wrapped up and she has burns.

"She had burns to her face - she's conscious, she was taking oxygen and pain relief as well.

"She seemed to have burns all over her body from top to toe."