People run from the Route 91 Harvest country music festival after gunfire is heard. Photograph:( AFP )
Police have said more than 50 people were killed in the shooting at a country music festival in Las Vegas.
Police have identified the gunman as Stephen Paddock.
Police said more than 200 people were injured after Paddock opened fire at the Mandalay Bay casino and resort.
Police had earlier described the suspect as being a local Las Vegas man who acted alone.
Authorities were however seeking an Asian woman who police described as a companion of the suspect, Reuters quoted a top police official as saying.
They said that rumours of other shootings in the area were false. Off-duty police are believed to be among the victims.
Police had earlier confirmed that they had shot the gunman.
Confirming that one suspect is down. This is an active investigation. Again, please do not head down to the Strip at this time.— LVMPD (@LVMPD) October 2, 2017
The shooting took place on the last night of the three-day Route 91 Harvest festival, a sold-out event attended by thousands and featuring top acts such as Eric Church, Sam Hunt and Jason Aldean.
Aldean was performing on Sunday night when the rampage began but that he had been bundled safely off stage at the event outside the resort, US media reported.
Two gunmen who had shot at a bodyguard and police were on the 32nd floor of the hotel, Reuters reported quoting a Twitter user who cited police scanners.
Another Twitter user posted that the hotel was on lockdown.
Witnesses heard numerous gunshots where police tactical teams were searching for the attacker, according to reports on CNN and in the New York Times.
The Las Vegas Police has asked people to avoid the area.
We're investigating reports of an active shooter near/around Mandalay Bay Casino. Asking everyone to please avoid the area. #LVMPDnews— LVMPD (@LVMPD) October 2, 2017
Several people including a police officer had been shot at a nearby outdoor concert, the Las Vegas Sun newspaper reported.
The Las Vegas hospital was taking in "several" people with gunshot wounds, University Medical Center spokeswoman Danita Cohen told the paper.
Video footage circulating on Twitter purportedly of the Mandalay Bay showed a crowd enjoying a concert before what sounds like volleys of automatic gunfire halt the performance.
The rampage was reminiscent of a mass shooting at a Paris rock concert in November 2015 that killed 89 people, part of a coordinated attack by Islamist militants that left 130 dead.