A shooting at a gay nightclub in Orlando, Florida, early Sunday left several people injured, police said.
"Shooting at Pulse Nightclub on S Orange. Multiple injuries. Stay away from area," Orlando police posted on Twitter.
When the shooting started, the nightclub posted on its Facebook page: "Everyone get out of Pulse and keep running."
CNN reported that the gunfire erupted at about 2 am (0600 GMT).
Anthony Torres, who was at Pulse, told CNN that the "shots did not sound like a regular handgun, it sounded like it was shooting repetitively and it wouldn't stop."
"So we knew what it was and we left there pretty quick. It was over 70 cop cars that were arriving there ... It happened so quick that people got separated from each other," Torres said.
Police also conducted a controlled blast at the club a few hours later.
"That sound was a controlled explosion by law enforcement. Please avoid reporting inaccuracies at this time," police tweeted.
On Friday, singer Christina Grimmie, who gained fame as a competitor on the US version of The Voice, died after being shot while signing autographs following a concert in Orlando.
The assailant was later identified as Kevin James Loibl, 27, who had travelled to Orlando from St Petersburg and was armed with two handguns and a hunting knife at the time of the attack, police said.
Grimmie, 22, had just finished performing at the city's Plaza Live concert venue when the shooting took place Friday night. She was taken to hospital where she died a short time later.