The father of the man who reportedly shot up an Orlando, Fla., nightclub early Sunday morning claims his son, Omar Mateen, became "very angry" when he saw two men kissing in downtown Miami a few months ago and thinks it may have been part of his son's motivation.

ADVERTISEMENT

At least 50 people were killed and more than 50 injured at Pulse, a gay nightclub in Orlando, overnight.

"We are saying we are apologizing for the whole incident," the father said to NBC News on Sunday.

"We are not aware of any action he was taking. We are in shock like the rest of America. This had nothing to do with religion," he said.

Authorities said the suspect engaged in a shootout with an officer who was working at the club at approximately 2 a.m. before going back into the club and taking hostages. A Special Weapons and Tactics (SWAT) team was sent inside the club to rescue the hostages at approximately 5 a.m.

Police said the suspect, who was killed inside the club during a shootout with police, had an assault-style rifle, a handgun and “some type of device.”

"It appears he was organized and well-prepared," Orlando Police Chief John Mina said, adding the shooter is not from the Orlando area.

An agent from the FBI's Orlando field office also said there are “suggestions” that the suspect may have had “leanings” toward radical Islamic ideology.

"We can't say definitively, so we're still running everything to ground," he added.

Law enforcement sources told CBS News the shooter was Omar Mateen, a U.S. citizen from Port St. Lucie, Fla.