At least 59 people are dead and more than 527 hospitalised after a shooter opened fire at a music festival in Las Vegas, police have confirmed.
The gunman fired from the 32nd floor of the Mandalay Bay Hotel and Casino along the famous entertainment strip, shooting down into a 20,000-strong crowd at the Route 91 country music festival at approximately 10pm local time on Sunday night.
It is now the deadliest mass shooting in US history.
The gunman has been named by the Las Vegas Metropolitan Police Department as 64-year-old Stephen Paddock, of Mesquite, Nevada.
Police used explosives to blast their way into the casino room where the gunman was situated but it is believed the shooter had already killed himself before they entered.
Paddock is considered to be the "sole aggressor", acting as a "lone wolf" shooter. The motives for his actions are as yet unknown.
More than ten rifles found were in Paddock's hotel room, but he has no prior police history, police said.
Despite initial social media reports to the contrary, there were no other shooters believed to be on the loose in other hotels, with police later declaring the area a "static scene".
Las Vegas Police Department said they were "confident" they had located Marilou Danley, the woman believed to be the shooter's partner and wanted for questioning about the incident.
The Australian newspaper has reported that Danley, 62, holds an Australian passport and is possibly "of Indonesian descent".
One off-duty police officer, whose name has yet to be released, has died, and two other on-duty police officers have been hospitalised, Sheriff Lombardo said.
One injured officer's condition was recently downgraded from critical to stable, while the other is believed to have minor injuries.
US President Donald Trump took to Twitter several hours after the mass murder, writing: "My warmest condolences and sympathies to the victims and families of the terrible Las Vegas shooting. God bless you!"
Chilling footage filmed on a mobile phone has emerged of the shooting, showing festival-goers running for their lives as a volley of gunshots ring out.
Concert-goers reported seeing muzzle flashes from the upper floors of the hotel and casino and the sound of what they described as automatic gunfire.
Seven News US correspondent Ashlee Mullany was only a few floors away as the shooter opened fire at the Mandalay Bay Casino.
Mullany was among a large number of evacuees and heard a "thundering volley of gunshots".
"It was utter chaos," she said.
A witness told News 3 Las Vegas said there were "bullets flying everywhere".
"We were on the furthest VIP stages away from Mandalay Bay and they were ricocheting everywhere we were," he said.
"They were firing from somewhere high and they were unloading clip, after clip, after clip."
Some officers took cover behind their vehicles while others carrying assault rifles ran into the hotel and casino.
A number of flights destined for the McCarran International Airport were diverted due to the shooting.