The authorities in Orlando, Florida, have been giving more details of the gun attack on a gay club early on Sunday, when 49 people were killed. The deadliest mass shooting in recent US history ended with gunman Omar Mateen being killed himself. The attack also left 53 people injured. Mateen had made a pledge of allegiance to the so-called Islamic State group. US President Barack Obama has described the killings as "an act of terror and hate". Obama used the shooting to once again call attention to the need for gun control laws in America.