22 injured in London Underground bomb attack

At least 22 people were injured after a bomb detonated on a packed London Underground train during the morning rush hour on Friday in what police are treating as a "terrorist incident".

Witnesses reported seeing passengers covered in blood and with facial burns and hair coming off at Parsons Green station in west London after the explosion on the train.

"At 8:20 this morning at Parsons Green station there was an explosion on a Tube train. We now assess that this was a detonation of an improvised explosive device," police counter-terror chief Mark Rowley said.

Twitter user @Rrigs, who posted pictures of a white bucket smouldering on the train, said: "Explosion on Parsons Green District Line train. Fireball flew down carriage and we just jumped out open door".

Explosion on Parsons Green district line train. Fireball flew down carriage and we just jumped out open door. pic.twitter.com/pGbfotbfsJ

— Rigs (@RRigs) September 15, 2017

The bucket looked like the type used by builders and there appeared to be cables coming out of it. According to Sky News, investigators suspect the device did not fully detonate.

The National Health Service said 18 people were taken by ambulance to hospital, while four others made their own way to hospitals.

Rowley said most of the people taken to hospital were being treated for "flash burns". The MI5 intelligence service is assisting investigators.

Prime Minister Theresa May said her thoughts were with the injured and will be chairing an emergency cabinet meeting later in the day.

'Sick and demented'

Armed police and sniffer dogs could be seen on the train and around the station, which is set in a leafy suburb of southwest London popular with well-off commuters and filled with chic cafes.

The station was closed, as well as an entire section of the District Line where it is located and police urged people to stay away from the area.

Local residents and businesses rallied together with businesses offering tea and the use of their toilets to local residents unable to get home.

One local resident, Charlie Craven, who was on his way to the station, said he heard a "massive bang".

"I looked around and the first thing I saw was an orange sort of fire, the sort of thing you see in a movie," he said.

The incident is the fifth terror attack in six months in Britain since March, when a lone attacker mowed down pedestrians and stabbed a police officer outside the British parliament.

London Mayor Sadiq Khan urged Londoners to remain "calm and vigilant".

"As London has proven again and again, we will never be intimidated or defeated by terrorism," he said in a statement.

US President Donald Trump said the attack was carried out by a "loser terrorist".

"These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!" he said on Twitter, without explaining further.

'Covered in blood'

Passengers described chaotic scenes at the station in the normally quiet part of west London.

Louis Hather, 21, was travelling to work and was three carriages down from where the explosion took place.

"I could smell the burning. Like when you burn plastic," he told AFP.

Hather saw a woman with burns being stretchered off.

He was trampled on as passengers stampeded out of the station and his leg was badly cut and bruised.

Sally Faulding, a 51-year-old teacher, said: "People were falling over each other."

Richard Aylmer-Hall, 52, told the Press Association: "There was panic, lots of people shouting, screaming, lots of screaming".

"I saw two women being treated by ambulance crews," he said.

Another witness, Sham, told the radio station he had seen a man with blood all over his face.

"There were a lot of people limping and covered in blood," he said.

Nicole Linnell, 29, who works for a fashion label, said: "We saw people running down the tracks. About 30 or 40 people.

"It was absolutely terrifying".

Natasha Wills, assistant director of operations at London Ambulance Service said: "Our initial priority is to assess the level and nature of injuries".

She said the ambulance service had sent "multiple resources" to the station, including a hazardous area response team.

A total of 35 people have been killed in four previous attacks in London and Manchester since March.

Three of those involved a vehicle ploughing into pedestrians.

The other attack was a bombing in May at a pop concert by US star Ariana Grande in Manchester which killed 22 people including children.