A manhunt is under way to find the person behind Friday's Tube bombing
Police are 'chasing down suspects' and trawling CCTV after Parsons Green attack
Terror threat level raised to 'critical' - meaning an attack is expected 'imminently'
The station reopened in the early hours of Saturday
29 people have been treated in hospital - police say 'most' had 'flash burns'
The explosion on the District Line train is being treated as terrorism
Police say it was caused by an 'improvised explosive device'
Anyone with information, photos or video should call 0800 789 321
The foreign secretary told Sky News: "I'm afraid my information is limited and it really is important not to speculate at the moment.
"Obviously, everybody should keep calm and go about their lives in a normal way, as normal as they possibly can.
"As far as I understand it, the British Transport Police and TfL are on it and they will be updating their websites as and when we have more information."
BBC Radio 5 live
Sham told BBC Radio 5 Live he was heading in to the station when he saw "hordes of people were trying to get down as quickly as they could."
Image source, Reuters"At first I thought they were in a bit of a rush or whatever but actually looked and the whole staircase was full of people.
There were people on the floor, all like toppling over each other just trying to get out as quickly as they could and there were loads of people crying and shaking", he said.
He added that there were "loads of people limping and covered in blood and stuff from like where they'd fallen over and hurt themselves."
Frank Gardner
BBC Security Correspondent
Image source, ReutersWhitehall officials say it's too early to pinpoint who they think caused the explosion at Parson Green but that an EOD (Explosive Ordnance Disposal) team is at the site looking at forensic clues.
Met Police SO15 Counter Terrorism Command are leading the response.
I would expect any intelligence leads are being followed up now.
The BBC's Sophie Raworth reports as emergency services attend the scene of a reported explosion on a District Line Underground train in south-west London.
Read MoreArmed police have been deployed to the area.
Image source, AFPBBC Radio 5 live
Image source, Richard Aylmer-Hall/PAEyewitness Luke told BBC Radio 5 Live there appeared to be "a sort of loud explosion".
"It happened just as we were pulling up to the Tube station so everyone just sort of piled out of the Tube and there was a distinct smell of burning."
"I certainly saw some burning injuries," he said, but added that "everyone behaved in the right manner as such, everyone got off as quickly as they can and you know supported everyone".
Emma, who was at Parsons Green station, says: "We were running down the stairs like.. it felt like for our lives... like sprinting, so happy I was wearing trainers...
"And I went down the stairs and after a while people were just piling on top of each other, because people were falling over trying to run so quickly.
"And there were two ladies underneath me and a little boy to my right, his head had been smacked into the concrete."
BBC presenter Sophie Raworth says she saw a woman stretchered away, with burns to her face and legs.
Image source, Emma StevieLondon Ambulance Service (LAS) have released a statement about the incident:
Quote Message"We were called at 08:20 BST to reports of an incident at Parsons Green underground station. We have sent multiple resources to the scene including single responders in cars, ambulance crews, incident response officers and our hazardous area response team, with the first of our medics arriving in under five minutes. Our initial priority is to assess the level and nature of injuries. More information will follow when we have it."
Natasha Wills, Assistant Director of Operations at London Ambulance Service
Media technology consultant Richard Aylmer-Hall who was sitting on the "packed" District line train said he saw several people injured, having apparently been trampled as they tried to escape.
The 53-year-old said "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.
"I saw crying women, there was lots of shouting and screaming, there was a bit of a crush on the stairs going down to the streets," he said.
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Alex Pope
BBC Local Live
The overnight fire at a factory and offices in north-west London will cause train disruption into London from Milton Keynes and Northampton for the rest of the day.
London Euston says the fire has "damaged the trackside retaining wall" and it is a "big job to fix".
The fire-damaged wall is in "danger of collapse and needs making safe before trains can safely run", a spokesman added.
Image source, London Euston
Image source, London EustonMore video footage has been shared online from the Harrow fire, which is affecting train services into London from Northampton and Milton Keynes.
Olivia Weetch filmed the fire last night.
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Below is footage taken of the Harrow fire by Ani Naz.
Nearly 60 firefighters were called to the blaze on Chantry Place, Harrow, close to midnight on Thursday.
As a result, trains through Headstone Lane have been suspended.
London Fire Brigade says a cordon was put in place around the warehouse blaze amid fears propane cylinders might explode.
The blaze is now under control, although 12 residents were told to leave their properties as a precaution.
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BBC London's Riz Lateef said she saw passengers suffering cuts and bruises as people panicked tried to eave the west London station.
The @districtline, external suspended Earl's Court to Wimbledon following reports of a fire or explosion on a train at Parsons Green.
There are reports of a fire at Parsons Green Tube station.
Police said they were called to the station at around 08:20 but do no have much more information at this stage.
BBC London's Riz Lateef is at the station and said passengers told her there was an explosion on the station and people panicked.
There is no service on London Midland, Virgin Trains and Southern between Milton Keynes Central and Euston.
Image source, @MPSHARROWVirgin trains to and from Scotland, north-west England the West Midlands and north Wales are starting or terminating at Milton Keynes.
London Midland is advising passengers not to travel on the route.
Nearly 60 firefighters were called to the blaze in Chantry Place, Harrow, at 23:47 BST on Thursday.