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. Twenty-two people were injured after a bomb blast on a packed London Underground train on Friday, the National Health Service said in a statement. / AFP PHOTO / Adrian DENNIS