The deadly bombing attack at an Ariana Grande concert in Manchester, England, highlights how difficult it can be to prevent attacks at “soft targets” like arenas.
Following an emergency Cobra committee meeting after the suicide bombing that killed 22 and injured 59 people in Manchester, Theresa May said the city had "fallen victim to a callous terror attack". "I know I speak for everyone in expressing my deepest sympathy to all who have been affected by this dreadful event and especially to the families and friends of those who have died or were injured," the monarch said.
Well-wishers deliver food and games for children gathered at a support centre for victims of the Manchester attack at football club Manchester City's Etihad Stadium. Video provided by AFP