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15 September 2017, 12:33
Mayor Sadiq Khan told LBC a manhunt is underway following the Parsons Green explosion.
18 people were treated in hospital after the terror incident on the District Line during rush hour this morning.
Speaking to LBC, the Mayor of London said: "There is a manhunt underway as we speak.
"The police and security services are following all lines of enquiry."
That led experts to say that they believe the police already know the suspect they are after.
Security analysts believe identifying the bomber could also be quick as the London Underground is the most CCTV-ed network in the world.
Video Shows Aftermath Of Parsons Green Explosion
Images of the improvised explosive device show a white builders' bucket inside a Lidl freezer bag. Inside the bag, block cloth can be seen along with some fairy lights, which experts believe could be used to detonate the bomb.
It is also understood that the device contained a timer.
Mr Khan urged calm among Londoners, saying: "Over the course of today and the next few days, you will see an increased police presents, not just in our public transport network, but also across London.
"There will also be additional TfL staff wearing hi-vis, not simply to reassure Londoners, but to make sure we're all doing our bit to stay vigilant."