(AP) — President Barack Obama says the nightclub shooting in Orlando was an “act of terror” and an “act of hate.”

He said Sunday that the FBI is investigating it as an act of terrorism and that no effort will be spared to determine whether the shooter was affiliated with terrorist groups.

Obama is speaking at the White House after 50 people were killed overnight at a nightclub in Florida. Officials have said 53 more are hospitalized.

Obama is noting that the killer targeted a gay nightclub. He says it’s a “sobering reminder” that an attack on any American is an attack “on all of us.”