Absolutely terrifying! From DailyMail.com:

This is the moment country singer Jason Aldean was forced to cut his performance in Las Vegas short as the concert turned into a bloodbath.

He had taken to the stage of the Route 91 Harvest Festival around 9.40pm and had been playing for about an hour when the first shots rang out.

Video taken from the back of the audience shows people crowded in front of the stage before what sounds like fireworks starts in the background.

WARNING - This is disturbing video: