Isis claims 'bucket bomb' attack on London Underground, UK threat level raised to 'critical'

Beirut, Sept 16: The Islamic State group has claimed responsibility for a bomb attack on a packed London Underground train on Friday, that injured at least 22 people.

"The bombing on a metro in London was carried out by a detachment of the Islamic State" group, it said in a statement published by its Amaq propaganda agency.

An improvised explosive device (IED) exploded+ on a packed underground train at a London station on Friday, injuring at least 29 people in the fifth terrorist attack this year, which Prime Minister Theresa May said was "clearly intended to cause significant harm".

The explosion, on a District Line Tube in the British capital's southwest, occurred as the train pulled into Parsons Green station. Commuters said they heard a bang and saw a fireball inside the carriage+ when the "bucket bomb" exploded.

Several people suffered facial burns, some reportedly were even trampled in the rush to escape. But none of the injuries were life threatening.

Pictures of a white bucket on fire inside a supermarket bag, with wires trailing on to the carriage floor of the train went viral on social media.

Investigators were examining what appears to be a circuit board recovered from the scene, news reports said.

Scotland Yard said it was a terror incident and they "assess" an IED triggered the blast. A hunt was on for a suspect the British media labelled as the "bucket bomber".+

Prime Minister Theresa May returned to London to chair a meeting of the government's emergency response committee. She called the incident a "cowardly attack" and said the national threat level had been raised a notch to its highest level, "critical".

This is the fifth terrorism incident in the UK this year.

The London Ambulance Service said 29 people have been treated in hospital. Police said that 'most' had 'flash burns'.

Scotland Yard's counter-terrorism squad, SO15, has taken the lead in the investigation from the transport police.

"Deputy Assistant Commissioner Neil Basu, the senior national coordinator for counter-terrorism policing, has declared it a terrorist incident," the police said in a statement earlier in the day.