Death toll from Las Vegas shooting climbs to 50
Las Vegas Metropolitan Police Department chief, Joe Lombardo, said during a press conference that the number of victims was provisional and the attacker had been killed by police at a nearby hotel.
"At this time there is in excess of 50 deceased and over 200 injured individuals," the police force said on its official Twitter account.
Earlier, Lombardo had spoken to reporters gathered near the scene.
"I cannot give you an accurate number at this point," Lombardo said. "We are comfortable that the primary aggressor in this event has expired and passed away and is no longer a threat."
Lombardo urged people to avoid going near the famous Las Vegas Strip.
The shooting took place at the end of the three-day Route 91 Harvest country music festival, an open-air event near the Mandalay Bay hotel and casino, at the southern end of the Strip.
The suspect acted alone and carried out the attack from the 32nd floor of the Mandalay Bay hotel where officers engaged what Lombardo described as "a shooter" and "a lone wolf type actor."
He said police had used an explosive device to enter the room where the aggressor had been and that two officers had been injured, one seriously.
He added that two off-duty police who had been attending the concert were among the victims.
The injured were taken to the University Medical Center and the Sunrise Hospital Medical Center, where many were in critical condition, he said.
The suspect was local, Lombardo said, adding that police were searching for a woman identified as Marilou Danley in relation to the attack.
Dozens of police cars and a team of rapid action special agents (SWAT) were swiftly deployed to the scene.
The shooting took place at around 10.00 pm local time (5.00 am GMT) while country singer Jason Aldean was performing on the closing day of the festival.
Bursts of shots could be heard in videos shared on social media, which showed scenes of people running away and trying to protect themselves.
Lombardo asked the public to supply police with any video recordings that might help investigators.
Police tweeted that they were "searching for two vehicles associated with the shooter: Hyundai Tucson Nevada/114B40 and a Chrysler Pacifica Nevade/79D401."
"Freeways have been reopened for thru traffic," LVMPD said, after police earlier shut down parts of the Las Vegas Boulevard.
The attack saw several flights to Las Vegas International Airport diverted to other hubs.