Oct. 2 (UPI) -- Fifty-nine people were killed and hundreds were injured late Sunday at an outdoor country music festival on the Las Vegas Strip -- in what is now the deadliest shooting attack in modern U.S. history.
The gunfire began around 10 p.m. on the south end of Las Vegas Boulevard during the Route 91 country music festival. Authorities said the shooter fired from the 32nd floor of the Mandalay Bay Hotel and Casino into a lot diagonally 500 yards across the street.
Automatic gunfire was captured on cellphone recordings of the concert, followed by panicked show-goers running for cover. Witnesses said the shooting lasted for 5 to 10 minutes.
Las Vegas police said 527 people were injured. The city's two trauma centers, University Medical Center and Sunrise Hospital Medical Center, were treating victims.
The attack is the deadliest mass shooting in U.S. modern history, surpassing the 49 killed by a gunman last year at the Pulse nightclub in Orlando, Fla.
Police identified the suspected shooter as Stephen Paddock, 64, a resident of Mesquite, 82 miles northwest of Las Vegas. He died from a self-inflicted gunshot wound, police confirmed Monday.
"Right now we believe it's a sole actor, a lone wolf type actor," Clark County Sheriff Joseph Lombardo said at a news briefing.
Lombardo said the shooter fired onto the 15-acre lot where about 22,000 had gathered to watch the final night of the festival.
Police recovered 23 firearms from the hotel room -- up from 10 earlier announced -- and another 19 firearms, explosives and ammunition at his Mesquite, Nev., home, Lombardo said Monday night. He said a number of the rifles in the hotel room had scopes.
NBC reported the suspected gunman made several large gambling transactions worth tens of thousands of dollars in recent weeks, according to law enforcement officials.
A U.S. official told CBS News there were no early signs of any ties to radical Islamic groups or signs of radicalization. The Islamic State said in two statements released by its pseudo-news agency Amaq, citing anonymous sources, that the gunman converted to Islam several months ago and the attack "in response to calls to target states of the coalition" battling the Islamic State.
Lombardo said police have located an Asian woman, Marilou Danley, who lived with the suspect since 2003, according to records obtained by the Reno Gazette-Journal. Police originally said she was with the suspect in Las Vegas but later said she is out of the country.
One off-duty police officer was among the dead. Also, two officers were being treated for injuries --- one officer was in critical condition and the other had minor injuries.
"It was was a horror show," concertgoer Ivetta Saldana told the Review-Journal. "People were standing around, then they hit the floor."
She said was attending the concert with a friend and hid in a sewer.
"We met someone at the gas station, a nurse, she was at the concert and she treated someone who was shot in the face, someone who was shot in the chest and someone who was shot in the liver," a man identified as Todd told CNN.
"Tonight has been beyond horrific," Aldean wrote on Instagram. "I still don't know what to say but wanted to let everyone know that me and my crew are safe ... It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night."
Las Vegas police were seeking footage or photographs of the events at the Mandalay Bay Resort and Casino.
The Bakersfield Police Department in California said several off-duty officers attended the concert. One was injured, according to KGET-TV. A number of off-duty police officers were at the show.
Roads around the area, including Interstate 15, were closed. At midnight, more than 25 flights were diverted from nearby McCarran International Airport, according to airport spokeswoman Christine Crews. People ran onto an airport runway while fleeing the shooting.
Nevada Gov. Brian Sandoval called it a "tragic and heinous act," adding that prayers "are with the victims and all affected by this act of cowardice.
Las Vegas Mayor Carolyn Goodman posted on Twitter: "Pray for Las Vegas. Thank you to all our first responders out there now."
Mandalay Bay, which opened in 1999, includes a 43-story tower, 3,309 hotel rooms, a convention center and a 12,000-seat events center. MGM Resorts International owns Mandalay Bay and several casino/hotels in Las Vegas.
Mandalay Bay, the MGM and the Tropicana were on lockdown until 8 a.m., at which point guests were allowed back into their rooms. Access to the 32nd floor of the Mandalay Bay was still restricted.