The father of the Orlando shooter has told a TV station that he has no idea why his son stormed a nightclub and killed at least 50 people.

Mir Seddique told NBC News: "I don't know why he did it. He is dead, so I can't ask him. I wish I knew."

Just hours after federal officials say his son, Omar Mateen, went on the deadliest shooting rampage in U.S. history, Mir Seddique was at a loss to explain what happened in an interview with NBC News.  Fifty people were killed and 53 were injured at Pulse, a gay nightclub in Orlando, authorities say.

"I apologize for what my son did ... We are saying we are apologising for the whole incident. We weren't aware of any action he is taking. We are in shock like the whole country," Seddique told NBC News.

NBC News reported that the attacker’s father indicated that Mateen recently expressed anti-gay sentiments when he saw two men kissing in Miami a couple of months ago, but the official who is not authorized to comment publicly said investigators were still reviewing a wide range of possible motivations.

Seddique told NBC News "this has nothing to do with religion."

Investigators are interviewing members of Mateen’s family in an attempt to learn what may have prompted the assault, a federal law enforcement official said.