At least 50 people were killed in a shooting at Pulse nightclub in Orlando, Florida.
Orlando authorities are treating the June 12 shooting as an act of domestic terror and the FBI is involved in the investigation, CNN reports.
At around 2 a.m., the gunman was engaged in a shootout with an officer outside of Pulse, a popular gay nightclub. The suspect then ran inside with an assault-type weapon, a handgun and another device, and opened fire on patrons.
At least 53 people were injured, and 50 killed in the mass shooting, Orlando Mayor Buddy Dyer said, according to BBC News.
Officials confirmed the gunman was Omar Mateen, a U.S. citizen from Florida.
"It's just shocking," Christopher Hansen, who was in the club, told CNN. “[Gunshots,] just one after another after another. It could have lasted a whole song.”
"Everyone get out of Pulse and keep running," the nightclub posted on its Facebook page shortly after the shooting began.
The device Mateen had, which was possibly explosive, was strapped to his body, according to CNN sources. Authorities do not know whether the device was real or not.
A canine unit reportedly found explosives inside Mateen’s car.
He was shot and killed by police after they broke down the nightclub’s door with an armored vehicle following a standoff that lasted at least three hours.
"It's appears he was organized and well-prepared," Orlando police chief John Mina said.
Investigators are considering different motives in the case, but they “have suggestions the individual has leanings towards (Islamic terrorism), but right now we can't say definitely," Ron Hopper, assistant special agent in charge of the FBI’s Orlando bureau, said.