A number of people were reported to have been shot early on Sunday at a gay nightclub in Orlando, Florida, local media said.
The violence erupted at the Pulse nightclub, which urged patrons in a post on its Facebook page to “get out” and “keep running.”
Local media reported that a number of people, ranging from seven to as many as 20, had been shot but there were no confirmed fatalities. Several patrons posted on social media that a gunman was holed up inside and was holding hostages.
One man who says he was inside the club at the time and posted videos of the scene, said on his Facebook page that shots had been fired inside the club and people were “screaming that people are dead”.
“They are just pulling people out in stretchers loading them up,” Anthony Torres wrote.
Local TV reporter Stewart Moore tweeted that he had been told by a source that more than 20 people had been shot.
He said the attacker was still inside the nightclub with hostages, and was feared to be wearing a bomb.