At least 58 people were killed and 515 were injured in Las Vegas Sunday night when a gunman opened fire on a music festival crowd from the 32nd floor of the Mandalay Bay Resort and Casino. It was the deadliest shooting in modern U.S. history, AP reported.

The "nonstop gunfire," according to one witness, sent more than 22,000 country music fans scrambling for their lives. Police say the lone suspect had at least 10 rifles when he was found dead in a Mandalay Bay hotel room.

Authorities have identified the suspected gunman as Las Vegas resident Stephen Paddock, 64, who committed suicide before police arrival.

The Islamic State claimed responsibility for Las Vegas shooting.