The police said the shooter killed himself before cops entered his room on the 32nd floor of the Mandalay Bay Hotel and Casino on the famous Las Vegas Strip. They had earlier said he had been engaged and killed. "We believe the individual killed himself prior to our entry," Las Vegas Sheriff Joseph Lombardo told a news conference.

The lone suspect opened fire on a crowd of more than 22,000 concert-goers at the open-air concert, the Route 91 Harvest Festival across the street below, from the hotel room at about 10:08 pm on Sunday.

The police SWAT responded to a call, breached the hotel room and found the suspect dead. In the room, the police found over 10 guns including machine guns. More weapons were seized from Paddock's home in Mesquite, about 145 km northeast of Las Vegas,

As Stephen Paddok opened fired from the 32nd floor hotel room, people screamed and fled in panic, footage captured on smartphones showed. Photos showed people cowering in the street or running in terror, as well as what appeared to be several bodies lying prone on the ground.

In a subdued televised address, President Trump called the massacre an "act of pure evil". Several world leaders have condoled the deaths in the shooting that Russian President Vladimir Putin described as "shocking in its cruelty" and British Prime Minister underlined was "an individual shooting randomly".

His brother Eric Paddock said in a phone interview the family was "horrified" and "bewildered" at the events. He said his brother did not belong to a political or religious organisation, and had no history of mental illness. Their father had been a bank robber who for a time was listed on the FBI's "Ten Most Wanted" list of fugitives.

Chart-topping country singer Jason Aldean was on stage at the time of the shooting, which came towards the end of the sold-out concert. A shocked Aldean told his fans via Instagram that he and his band were safe. "Tonight has been beyond horrific... It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night," the singer said.

Las Vegas's casinos, nightclubs and shopping are a major draw for some 3.5 million visitors from around the world each year and the area was packed with visitors when the shooting broke out.

The 400-feet tall hotel is near McCarran International Airport, which said on Twitter it had temporarily halted flights after the shooting. Later, the airport said that some flights had resumed.