A "crazed lunatic" turned an outdoor concert into a bloodbath, killing 58 people in what is now the deadliest mass shooting in modern US history.

Thousands of country music fans ran for cover Sunday night as a gunman fired hundreds of bullets at them from a hotel on the Las Vegas Strip, officials said.

Another 515 people were hurt in the gunfire and ensuing stampede at a Jason Aldean concert, police said.