Islamic State group claims London attack

The Islamic State group today claimed responsibility for a bomb attack on a packed London Underground train the same day that injured at least 29 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.

The incident occurred during rush hour in the morning on a District Line Tube train as it pulled into Parsons Green station. 

An explosion caused by a suspected "bucket bomb" on a London Underground train at Parsons Green is being treated as a "terrorist attack", Scotland Yard has said. 

The London Ambulance Service said 22 people have been taken to the hospital. 

Assistant commissioner Mark Rowley says a suspected Improvised Explosive Device is thought to be responsible for the blast. 

He said more police would be deployed across London particularly on the transport network. He refused to say whether anyone had been arrested. 

Several people are said to have suffered facial burns after the blast in a bucket towards the rear of the District Line train. Some commuters reportedly were trampled and suffered crush injuries in the rush to escape. 

Scotland Yard's counter-terrorism squad, SO15, arrived at the scene at Parsons Green Tube station and took the lead in the investigation from the British Transport Police. 

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

"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," the statement said. 

"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," it said. 

Downing Street said Prime Minister Theresa May was "receiving regular updates" on the situation. 

"My thoughts are with those injured at Parsons Green and emergency services who are responding bravely to this terrorist incident," May tweeted. 

Some of the injuries are believed to be related to the direct impact of the explosion involving a large white plastic bucket in a supermarket plastic bag in one of the carriages. Images of the bucket with wires sticking out have emerged on social media.