Police have identified the suspected gunmen in a Florida shooting that left at least 50 people dead as a 29-year-old U.S. citizen whose family is believed to be from Afghanistan.

Omar Mateen died in an early-morning shootout with police on June 12, 2016 at the Pulse nightclub, in which at least 53 others were also injured.

Deadliest Mass Shooting in U.S. History

Reports state that the FBI is treating the deadliest mass shooting in U.S. history as an act of terrorism. Federal officials are now also feverishly investigating to determine if Matten had any ties to any radical terror groups.

Armed with an assault-style rifle, handgun and a suspected explosive device, Mateen took hostages at the popular, Orlando gay nightspot before being shot dead by police at around 5 a.m.

Mateen's father has since told authorities his son may have harbored "anti-gay" sentiments. Orlando Mayor Buddy Dyer has declared a state of emergency and President Obama is expected to release a statement on the situation in the coming hours.

"It's appears he was organized and well-prepared," said Orlando police chief John Mina.

At least nine officers were involved in the shootout with Mateen, who reportedly had several explosive devices strapped to his body and others stored in his vehicle.

Shots first rang around 2 a.m., and an officer who was working at the club engaged Mateen in a shootout before he fled inside the club. 

Orlando Residents Told to Avoid Area

Orlando police warned residents to stay away from the area, but declined to reveal how the number of casualties, insisting details will be available later.

Mateen is reported to be from nearby Fort Pierce, estimated to be about 120 miles southeast of Orlando. All across the area, emergency and medical centers were placed on lockdown as medical staffers hustled to treat the injured.