At least 59 people were killed and 527 injured after a gunman opened fire on more than 22,000 concertgoers in Las Vegas, police said Monday, in what was the deadliest mass shooting in modern U.S. history.
Bursts of gunfire rained down on the Route 91 Harvest country music festival across the road from the Mandalay Bay hotel on the south side of the Las Vegas Strip.
The suspect, identified as Stephen Paddock, 64, of Mesquite, Nevada, was found dead in his 32nd-floor room at the hotel in an apparent suicide, Las Vegas Metropolitan Police Department Sheriff Joseph Lombardo said.
Investigators said Paddock had no known connection to international terrorism, and there were no other shooters. Nonetheless, ISIS claimed responsibility and offered no evidence.
"We have determined to this point no connection with an international terrorist group," the FBI said. "We will continue to work with our partners to ensure that this is factually, thoroughly and absolutely investigated to be able to bring comfort and peace back to this community."
Police told The Wall Street Journal that the shooter appears to have used a fully automatic rifle. Law enforcement authorities discovered a cache of at least 18 other firearms in the shooter's hotel room where he fired upon those below. Another 18 firearms were retrieved from the suspect's house, authorities said late Monday.
Videos posted on social media showed large crowds ducking for cover amid sustained blasts of gunfire.
Video tweet of people ducking for cover
The FBI requested that anyone with video or photos regarding the shooting call 1-800-225-5324.
Lombardo said a woman who was a "companion" of Paddock, Marilou Danley, has been located, as were two vehicles associated with the shooter: a Hyundai Tucson and a Chrysler Pacifica, both with Nevada number plates. Police say Danley was not with Paddock when he checked into Mandalay Bay. Paddock was utilizing some of her identification, Lombardo said, adding that police "have had a conversation with her," and that she was not believed to have been involved "at this time."
During the shooting, police told people to avoid heading to the south end of the Strip and said it was investigating an active shooter. Police said Las Vegas Boulevard was shut down southbound at the Tropicana.
The number of dead surpassed the death toll in the June 12, 2016, rampage at the Pulse gay nightclub in Orlando, where 49 people were slain. Police said among the injured were two on-duty officers. One was in stable condition after surgery and the other sustained minor injuries.
Lombardo also said reports on social media that there were multiple shooters and explosives used were false.
All flights were temporarily halted at Las Vegas McCarran International Airport, authorities said. Just before 1 a.m., McCarran tweeted that "limited flight activity" had resumed but travelers should expect delays.
'Pandemonium'
Jon Bessett, one of the concert attendees, described the scenes as "pandemonium." He told NBC News that around 10 p.m. Sunday, he heard gunshots but country music star Jason Aldean and his band continued playing. Further gunshots followed and the band ran off stage.
"Everyone was running, people were getting trampled," Bessett said. He then ran out over to the Luxor hotel nearby but still had friends at the concert, Bessett said.
"We ran as quick as we could into hotel and tried to get on the elevator but couldn't get in.
@Bessette20: 1st responders ducked behind Luxor, as I was running #LasVegas #route91harvest
Chilling videos on social media show Aldean running off stage. He posted on Instagram shortly after informing people that he and his crew were safe.
Tweet video of Aldean running off stage.
"My thoughts and prayers go out to everyone involved tonight. It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night," Aldean wrote on Instagram.
For more on the Las Vegas attack, see Las Vegas massacre: Scenes from the deadliest mass shooting in modern US history
Mandalay Bay, which is owned by MGM Resorts, was on lockdown during the shooting, according to one social media user.
The hotel and casino later released a statement on its official Twitter account.
Trump sends condolences
Governments and celebrities posted their responses to the massacre online. President Donald Trump sent his condolences to the victims.
"We are monitoring the situation closely and offer our full support to state and local officials. All of those affected are in our thoughts and prayers," White House press secretary Sarah Sanders said in a statement.
Vice President Mike Pence also tweeted about the tragedy.
U.K. Prime Minister Theresa May of Britain also tweeted from her office's official Twitter account.
Many celebrities also offered their well-wishes.
WATCH: Live Nation responds to Las Vegas shooting
Clarification: The shooting in Las Vegas was the deadliest mass shooting in modern U.S. history.