ORLANDO, Fla. (AP) — The massacre at an Orlando nightclub that claimed 49 lives is the worst mass shooting in U.S. history.

Police Chief John Mina confirmed at a news conference Sunday morning that 49 people were killed, up from 20 as earlier reported.

Mayor Buddy Dyer says 53 more are hospitalized after the early Sunday incident. He says the shooter is among the dead.

Dr. Mike Cheatham is a trauma surgeon at Orlando Regional Medical Center, where 46 patients were taken. The majority are in critical condition. He tells The Associated Press, “I think we will see the death toll rise.”

Police say the shooter used an AR-15-type assault rifle on all the victims.

Officials at the news conference also say they have securing the suspect’s vehicle, a van, right outside the club.