A video posted on social media captured the moment the gunshots began, forcing Aldean and his band to abruptly stop mid-song and leave the stage at the music festival in the Nevada gambling hub.
The video shows people screaming as the gunman fires multiple rounds on the crowd, with one woman yelling, "Oh my god," and others calling on others to "Get down."
"Tonight has been beyond horrific. I still don't know what to say but wanted to let everyone know that me and my crew are safe," Aldean wrote on his Instagram account.
The two-time Academy of Country Music Entertainer of the Year Award winner has sold 15 million albums.