A gunman has killed at least 58 people and wounded more than 500 at a country music festival on the Las Vegas Strip on Sunday, shooting down from the 32nd floor of a hotel, where he was shot dead by police.

ISIS claimed the Las Vegas attack and said the shooter converted to Islam months ago, but provided no evidence to back their claim.

Investigators have so far found “no connection” between international terrorist groups and a mass shooting in Las Vegas that killed at least 58 people and injured more than 500, an FBI special agent said Monday.

The ISIS group, through its propaganda arm, had earlier claimed responsibility for the attack, claiming the shooter was a recently converted “soldier.” Police said the attack was carried out by Stephen Paddock, a 64-year-old retired accountant.

“As this event unfolds we have determined to this point no connection with an international terrorist group,” said Aaron Rouse, the special agent in charge of the Las Vegas office of the FBI.

The death toll, which police emphasized was preliminary, would make the attack the deadliest mass shooting in US history, eclipsing last year's massacre of 49 people at an Orlando night club.

Some 22,000 people were in the crowd when the man, identified as area resident Stephen Paddock, opened fire. His shooting sent panicked people fleeing the scene, in some cases trampling one another, as law enforcement officers scrambled to locate and kill the gunman.

Shocked concertgoers, some with blood on their clothes, wandered the streets after the attack.

At least 406 people were taken to area hospitals with injuries, the Las Vegas Metropolitan Police said.

No further information on Paddock, 64, was given by police who said they had no information yet about his motive.

Paddock shot himself before police entered the hotel room he was firing from, Clark County Sheriff Joseph Lombardo told reporters.

Earlier reports indicated that Paddock, who had more than 10 rifles in his hotel room, had been shot by police.

Paddock was not believed to be connected to any militant group, Clark County Sheriff Joseph Lombardo told reporters.

a music festival on the Las Vegas Strip in Las Vegas. (Reuters)

"We have no idea what his belief system was," Lombardo said. "We've located numerous firearms within the room that he occupied."

The dead included one off-duty police officer, while at least one other officer was critically injured, Lombardo said. Police warned the death toll may rise.

Police said that the shooter was taken "down" after officers swarmed over the famous boulevard following reports of multiple shots being fired from the Mandalay Bay casino resort towards thousands of fans at a country music concert.

Pictures taken at the scene showed revelers cowering in the street or running in terror, as well what appeared to be several bodies lying prone on the ground.

A local hospital was taking in "several" people with gunshot wounds, University Medical Center spokeswoman Danita Cohen told the local Sun newspaper.

Video footage circulating on social media showed a large crowd enjoying a concert as part of the Route 91 country music festival just outside the casino before what sounded like volleys of automatic gunfire halted the performance.

A witness told local TV news station KLAS that he saw someone several stories high firing hundreds of shots into a crowd of people.

Police however denied reports of multiple shooters: "At this time we do not believe there are any more shooters," the department wrote on Twitter.

The suspected shooter's brother, Eric Paddock, said the family was stunned by the news.

"We have no idea. We're horrified. We're bewildered and our condolences go out to the victims," Eric Paddock said in a brief telephone interview, his voice trembling. "We have no idea in the world."

US President Donald Trump offered his condolences to the victims via a post on Twitter early Monday.

"My warmest condolences and sympathies to the victims and families of the terrible Las Vegas shooting. God bless you!" Trump said.

The rampage was reminiscent of a mass shooting at a Paris rock concert in November 2015 that killed 89 people, part of a wave of coordinated attacks by Islamist militants that left 130 dead.

The concert venue was in an outdoor area known as Las Vegas Village, across the Strip from the Mandalay Bay and the Luxor hotels.

"Our thoughts & prayers are with the victims of last night's tragic events," the Mandalay Bay said on Twitter.

Shares of US casino operators fell in premarket trading on Wall Street, with MGM Resorts International, which owns the Mandalay Bay, down 5 percent. Melco Resorts & Entertainment Ltd, Wynn Resorts Ltd and Las Vegas Sands Corp each fell 1 to 2 percent.

source: Alarabiya