"It is hard to find a rational justification that explains the ease with which people can buy firearms, including assault rifles, in spite of prior criminal backgrounds, drug use, histories of domestic violence and mental illness, or direct contact with extremists - both domestic and foreign," UN High Commissioner for Human Rights Zeid Ra'ad Al Hussein said in a statement after a gunman shot dead 49 people in a gay club Sunday.
The man armed with an assault rifle and pledging loyalty to Daesh (also known as ISIL and ISIS) killed and injured scores of people during a celebration at Pulse nightclub in Orlando early Sunday in the deadliest mass shooting in US history.
Later, Daesh claimed responsibility for the attack through its so-called Amaq news agency.