A gunman has killed 50 people and wounded another 53 at a gay nightclub in Orlando, Florida. It was the worst mass shooting in U.S. history. President Barack Obama, in an address to the nation Sunday, called the attack “an act of terror and an act of hate.” He said the American people are united in grief and outrage. Obama praised the police and others who worked to rescue the hostages and end the attack. The president also called the attack a “further reminder of how easy it is for someone to get their hands on a weapon.” Obama’s comments mark his fifteenth address linked to a mass shooting during his presidency. Many families still do not know the fate of their loved ones who were at the Pulse nightclub in Orlando. Police have identified the shooter as Omar Saddiqui Mateen. He worked as a security guard since 2007. He was killed at the scene in a gunfight with police. Mateen is a U.S. citizen born in New York. His parents are from Afghanistan.