Everything We Know So Far About the Tube Terror Incident

Twenty-three London Underground passengers were injured after an explosion on a District line train in west London this morning.

Scotland Yard's counter-terrorism unit has taken the lead in the investigation, and declared it a terrorist incident, with Met police sources saying the explosive device was "viable" and that it only partially exploded, reports the Guardian. Sources also said there is no belief that the incident was part of a coordinated attack across London, and denied reports that there was a knifeman on the train.

London Mayor Sadiq Khan has told LBC that "there is a manhunt underway as we speak".

Twenty-three people are being treated in four hospitals across London, with it understand that "most" are being treated for "flash burns", according to PA. London Ambulance Service tweeted a statement confirming that 19 people were taken to hospital, and four people admitted themselves.

Following the attack, one Tube passenger told the BBC: "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, Richard Aylmer-Hall, told the Guardian: "Suddenly there was panic, lots of people shouting, screaming, lots of screaming. 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."

Other witnesses reported seeing a "fireball" and a "wall of flame" flying through the Tube carriage.

Pictures and video have since emerged of a burning white plastic bucket inside a Lidl bag.

Paramedics, armed police and firefighters were sent to Parsons Green station at around 8:20AM and closed off the surrounding area.

Prime Minister Theresa May is set to chair a Cobra emergency committee meeting this afternoon to discuss the incident, and in a statement has 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."

London Mayor Sadiq Khan said he "utterly condemns the hideous individuals who attempt to use terror to harm us and destroy our way of life", and the urges "all Londoners to remain calm and vigilant".

American President Donald Trump tweeted: "Loser terrorists must be dealt with in a much tougher manner.The internet is their main recruitment tool which we must cut off & use better!"

This story is developing and this article will be updated