Members of the emergency services work near Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. "We are aware of an incident at Parsons Green tube station. Officers are in attendance," London's Metropolitan Police said on Twitter. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)
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How Underground terror incident unfolded
London police are treating an incident on a train at Parsons Green Tube station as terrorism. Witnesses saw a "small explosion" on the District Line train.
01:36 - Source: CNN
London tube terror attack 8 videos
Members of the emergency services work near Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. "We are aware of an incident at Parsons Green tube station. Officers are in attendance," London's Metropolitan Police said on Twitter. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)
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How Underground terror incident unfolded
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LONDON, ENGLAND - SEPTEMBER 16: Police vans sit parked outside Portcullis House in Westminster on September 16, 2017 in London, England. An 18-year-old man has been arrested in Dover in connection with yesterday's terror attack on Parsons Green station in which 30 people were injured. The UK terror threat level has been raised to 'critical'. (Photo by Jack Taylor/Getty Images)
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Police: Second man arrested in London attack
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LONDON, ENGLAND - SEPTEMBER 16: Police and armed police patrol in Westminster Underground station on September 16, 2017 in London, England. An 18-year-old man has been arrested in Dover in connection with yesterday's terror attack on Parsons Green station in which 30 people were injured. The UK terror threat level has been raised to 'critical'. (Photo by Jack Taylor/Getty Images)
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Police forensics officers works alongside an underground tube train at a platform at Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. British police are treating an incident on a London Underground train on Friday as an act of terrorism, saying "a number of people" had been injured. "Terrorist incident declared at Parsons Green Underground Station," police said in a statement. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)
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London witness: Flames rose to the ceiling
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London Metropolitan Police press conference on terror attack on Septemer 15, 2017
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London police: Investigation is ongoing
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Members of the emergency services work alongside an underground tube train at a platform at Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. "We are aware of an incident at Parsons Green tube station. Officers are in attendance," London's Metropolitan Police said on Twitter. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)
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Police: Tube incident declared terror event
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