A gunman opened fire from a hotel room above a packed, outdoor concert in Las Vegas, killing at least 59, wounding 527 more and prompting chaos as the panicked crowd scrambled for cover amid the deadliest mass shooting in modern U.S. history.

Gunman Stephen Paddock, 64, was found dead by officers who stormed his 32nd-floor room at the Mandalay Bay Resort and Casino, said Clark County Sheriff Joe Lombardo, who announced the death toll and said it could rise.

Lombardo described Paddock, of Mesquite, Nev., as "a distraught person intent on causing mass casualties." Lombardo said Paddock was likely a "lone wolf" and that a motive for the shooting had not been determined.

"This is a crazed lunatic full of hate," Las Vegas Mayor Carolyn Goodman said. "This has been a hugely traumatic time for all of us."

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UPDATES: Las Vegas Strip shooting: More than 50 dead, more than 500 others injured