TWITTER Anti-terror police arrested a teenager after a suspicious device was found on the Tube

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Officers tasered and arrested a 19-year-old man after a "viable improvised explosive device" was found on a Tube train at North Greenwich. North Greenwich tube station was evacuated for nearly seven hours after London Underground staff found the suspect package on an eastbound Jubilee Line train. But experts warned the IED may have been just the first in a co-ordinated attack on the capital. Armed police swooped on the teenage suspect as he walked down Holloway Road in north London, Tasering him in the street. One witness claimed officers shouted "armed police, don't struggle", as they wrestled him to the floor. The alarm was raised after a passenger reportedly found the device, described as "a bag full of wires", on an eastbound Jubilee Line train at North Greenwich station at about 11am. Bomb disposal experts carried out a controlled explosion. The suspect teen was taken to a London police station, where he remains in custody. Witnesses described the suspect as white, bearded, and wearing a hoodie. Metropolitan Police said a Taser was discharged during the arrest but no shots were fired. A Ministry of Defence source told The Telegraph it is possible the device was part of a wider terror plot and more attacks may have been planned. There are increased patrols across London as police desperately try to avoid a deadly terror attack striking the capital.

The 19-year-old man was arrested on suspicion of the commission, preparation and instigation of terrorism acts, under Section 41 of the Terrorism Act 2000 Metropolitan Police

An MoD insider said: "This increase is in response to the discovery of a suspected viable improvised explosive device (IED) on a London Underground train yesterday. "It is unknown who placed the device and what their motivation was. Therefore it remains possible that the perpetrator may attempt to place further devices. The threat level will continue to be reviewed as further information is received." A witness, who identified himself only as 'Ali" told the BBC the suspect was white, had a beard and was wearing a hoodie when officers swamped him as he walked down the street. He said: "The armed police, I think five of them, ran behind him and put him on the floor. "They were shouting: 'armed police, don't struggle'. Everything happened so quick." In a statement , the force said: "The 19-year-old man was arrested on suspicion of the commission, preparation and instigation of terrorism acts, under Section 41 of the Terrorism Act 2000. "He has been taken to a London police station where he remains in custody." The suspect device is being forensically examined.

BBC This is the horrifying moment terror officers pounced on a suspect on Holloway Road

BBC Police swooped on the 19-year-old who they suspect of planting the explosive device in Greenwich

Police are yet to release details of the device but one source claimed tube staff found a "bag full of wires". The public have been warned to remain vigilant and alert as armed police carry out extra patrols. Metropolitan Police said in a statement: “The item is currently being forensically examined and we await the results of that examination. “The Met and British Transport Police have been working tirelessly since the item was found to follow up all potential leads. “Officers are keeping an open mind regarding any possible motive. They are not looking for anyone else in relation to this investigation at this stage.

TWITTER Armed police seized the suspect in Holloway Road, north London

TWITTER The Metropolitan Police said a Taser was discharged during the arrest

“Police are urging anyone who saw anything suspicious on this particular train or anywhere else to call the Anti-Terrorist Hotline on 0800 789 321, in an emergency always call 999. “Officers continue to encourage the public to remain vigilant and alert at all times and report anything suspicious to police. “The public will see more officers, including armed police, in and around transport hubs to provide reassurance around public safety. “The London transport system is operating as normal today.

"High visibility patrols by BTP officers on the underground and at stations will remain in place today to reassure the travelling public as they start their weekend. Anyone with any concerns should speak with officers who will be happy to help. “Police continue to appeal to anyone with information to call the Anti Terrorist Hotline on 0800 789 321. "The public is urged to remain vigilant and to report any suspicious activity to the police through the anti-Terrorist Hotline or in an emergency 999.” The police swoop came after hundreds of passnegrs were evacuated and a controlled explosion was carried out on the device found on a train at North Greenwich station.

PA Police sealed off North Greenwich station as officers blew up the suspect device

GETTY North Greenwich station was evacuated

North Greenwich station came to a standstill as specialist officers were called in over the security alert on the London Underground. British Transport Police officers responded at around 11am as the bomb scare sparked travel chaos for nearly seven hours. Mayor of London Sadiq Khan urged Londoners to remain calm after the arrest. He said: "Thanks to the outstanding professionalism of the Metropolitan Police, Transport for London staff and the British Transport Police, this situation was dealt with swiftly and safely and no injuries resulted.

Police terrorist training exercise Tue, May 10, 2016 Emergency forces and shoppers take place in a simulated terror attack at the Trafford Centre, Manchester Play slideshow Getty Images 1 of 31 Shoppers take place in a simulated terror attack at the Trafford Centre, Manchester