 "Fifty dead, 53 injured in Florida mass shooting at a gay nightclub in Orlando")
At least 50 people were killed and 53 others injured in a shooting rampage early on Sunday at an LGBT nightclub in Orlando, Florida, the Mayor of Orlando said.
Several news outlets have identified the gunman as Omar Mateen, a 29-year-old from Fort Pierce, Florida.
Orlando Mayor Buddy Dyer confirmed at a press conference that 50 people were killed in the shooting rampage. Earlier reports, citing police, had placed the toll at 20.
The Washington Post said the identity of the shooter was confirmed by relatives and law enforcement officials.
The shooter was killed in a shootout with police, as they broke into the night club to rescue 30 people held hostage there.
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Earlier, the police called it an act of terrorism, but said they did not yet know if it was domestic or international.
A man who was inside the club earlier described a situation of chaos outside as the number of casualties became apparent.
"There were just bodies everywhere... in the parking lot, they were tagging them - red, yellow - so they knew who to help first and who not to. Pants down, shirts cut off, they had to find the bullets. Just blood everywhere," an eyewitness said.
CCTV camera footage from the scene showed dozens of emergency vehicles at the scene and people being treated on the pavements.
Some of the injured were reportedly brought to the Orlando Regional Medical Center in police pick-ups.
One woman said she had received a text message and phone call from her daughter inside the club, who said she had been shot in the arm.
Some witnesses said they heard as many as 40-50 gunshots as the incident unfolded.
More than 100 people were reported to have been enjoying a Latin-themed night in the club, which calls itself the hottest gay bar in the city, when the attack began.
The shooter opened fire at around 02.00 a.m. (local time) as the club night was coming to a close.
"We heard rapid fire go off. In the room I was in, people went down to the floor. I wasn't able to see the shooter or people get hurt, at some point, there was a brief pause, and a group of us got up and went to the exit that leads to the patio area outside. We found an exit and after that... I just ran," Anthony Torres, an eyewitness said.
He also heard people screaming that others in the nightclub were dead.
According to the Mass Shooting Tracker, there were 372 mass shootings -- defined as a single incident that kills or injures four or more people -- in the US in 2015. Some 475 people were killed and 1,870 wounded.
The latest incident comes as Orlando is still reeling from the fatal shooting on Friday night of 22-year-old singer Christina Grimmie following a concert in the city.
She was signing autographs when she was shot by 26-year-old Kevin James Loibl, who then killed himself. It is not clear what Loibl's motive was.