Islamic State’s news agency Amaq has said the terror group has taken responsibility for the bombing on a Parsons Green underground train.

A manhunt is underway after an improvised explosive device failed to fully detonate on a London underground train, filling carriages with “acrid smoke” and injuring dozens.

Several witnesses and media have reported that passengers have suffered “facial burns”, with authorities confirming that 29 people were injured, mostly from flash burns, but none seriously.

The device was described as a white builders’ bucket in a foil-lined bag with wires coming out of the side and fire from the top. Sources are reporting the device had a timer.

Police are currently searching for a perpetrator.

Live updates below…

– 10:55 am BST: Former counter-terror chief: ‘100 per cent certain’ incident was Islamist jihadist. –

Former counter terror chief Major General Chip Chapman told Sky News he believes that “you can almost certainly say this is in the Islamist Jihadist violence” stream of terror threats, as opposed to right wing extremism or Irish Republican dissidents.

Noting that “It seems to me this bomb at the moment malfunctioned”, he drew parallels to the Boston “pressure-cooker device” used during the Boston Marathon terror attack.

Maj. Gen. Chapman said that instructions on constructing pressure cooker bombs can be found in Islamic State’s Inspire magazine.

Saying he was “Absolutely 100 per cent sure” in his estimate that it was Islamist jihadist in nature, he said: “You don’t have any examples of right wing extremists or Republican dissidents using these kinds of devices in confined areas.”

– 10:40 am BST: Passenger describes “acrid smell”, bucket device in an insulated bag, children running in panic –

A witness spoke to Sky News that an “acrid smell” passed through the train cars before mass panic and a stampede ensued leaving children travelling to school getting knocked over.

The witness described the device as a white “builder’s bucket” in an insulated carrier bag with wires coming out of the side and flames out of the top.

He described the smell as chemical, rather than burning.

– 10:21 am BST: Met Police confirm – Incident being treated as a terrorist incident –

The Met’s Counter Terrorism Command are investigating after the incident at #ParsonsGreen tube station is declared a terrorist incident — Metropolitan Police (@metpoliceuk) September 15, 2017

– 10:15 am BST: Sky Sources – Incident being treated as a terror incident –

Sky News sources are claiming the incident is now being treated as a terror incident.

#BREAKING: Authorities have said Parsons Green explosion is being treated as a terror incident – https://t.co/qAWslx4Jx4 pic.twitter.com/r22WoKWq0D — talkRADIO (@talkRADIO) September 15, 2017

– 9:56 am BST: Sky News sources say counter-terrorism are on the scene –

Sky News reports that investigations are still being led by British Transport police but counter-terrorism police officers are on the scene.

Scotland Yard and intelligence are also monitoring.

Home Affairs Correspondent @skymarkwhite on latest on #ParsonsGreen incident: No. of people injured; Counter-terrorism detectives on scene pic.twitter.com/Swd8SqWCvj — Sky News (@SkyNews) September 15, 2017

Emergency Services are still at Parsons Green tube station. We continue to ask Londoners to avoid the area. More info as and when verified — Metropolitan Police (@metpoliceuk) September 15, 2017

– 9:35 am BST: Metropolitan Police confirm they are dealing with an incident at Parsons Green Station –

London Ambulance confirms that they were called to reports of an incident at 8:20 am on Friday morning, with multiple resources sent to the scene including ambulances, hazardous areas response teams, and medics. Armed police are also on the scene.

A witness has tweeted images of a white bucket in a Lidl bag on fire, believed to be a device that may have caused the incident on the District line carriage.

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

Closer image supposed bag that exploded inside subway at #ParsonsGreen in London, wires can be seen hanging out https://t.co/ITy0nsMRgj — Roeland Roovers (@r0eland) September 15, 2017

From Reuters: Stampede In London's Parsons Green Underground Station: Witness — BTVI Live (@BTVILiveNews) September 15, 2017

Parsons Green eyewitness: “There was a bit of a crush on the stairs. Some people got pushed over and trampled on." https://t.co/FiqNz8cxSg — LBC (@LBC) September 15, 2017

– 9:25 am BST: Media reporting severe burns injuries –

The BBC is reporting from the scene that people have suffered burns, with Sophie Raworth recounting that she saw a woman taken to ambulance with burns “from top to toe”.

.@sophieraworth saw woman taken to ambulance with burns "from top to toe" after explosion on train at Parsons Green https://t.co/bCKuWdNiZj pic.twitter.com/RvTnHq0T7E — BBC Breaking News (@BBCBreaking) September 15, 2017

– 9:00 am BST: Metropolitan Police confirm they are dealing with an incident at Parsons Green Station –

A Metropolitan Police spokesman said via Twitter: “We are aware of an incident at Parsons Green Tube station. Officers are in attendance. More info ASAP”.

We are aware of an incident at #ParsonsGreen tube station. Officers are in attendance. More info ASAP — Metropolitan Police (@metpoliceuk) September 15, 2017

From Reuters: Stampede In London's Parsons Green Underground Station: Witness — BTVI Live (@BTVILiveNews) September 15, 2017

Richard Hall, who was on board the train, told Sky News that though he did not witness the incident, he noted a sudden mass screaming, shouting, and a crush of people who were running down the far end of Parsons Green platform. He said a woman who was also on the train told him a small bag went off in flames.

Parsons Green explosion. Some people say there was a bag with wires on the train pic.twitter.com/l15MGp6W8p — Andrius Solopovas (@ASolopovas) September 15, 2017

This story is developing…