More than 50 people are confirmed dead—59 is the most recent number—and more than 500 injured after a “lone wolf” gunman opened fire during Jason Aldean’s set at the Route 91 Harvest Festival in Las Vegas last night (Oct. 1).

The male suspect, a 64-year-old local resident, has been killed. The suspect fired on the crowd from the 32nd floor of Mandalay Bay.

The three-day Route 91 Harvest festival started Friday and is reported to have attracted 30,000 attendees. The shooting began on the final night, during a performance by Jason Aldean.

After 49 people where killed at Pulse nightclub in Orlando, Fla., in June 2016, this is thought to be the worst mass shooting in U.S. History.

Country music artists who were performing last night at the festival or attending, including Chris Young, Jason Aldean, Jake Owen and more, have posted messages on social media.

Tonight has been beyond horrific. I still dont know what to say but wanted to let everyone know that Me and my Crew are safe. My Thoughts and prayers go out to everyone involved tonight. It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night. #heartbroken #stopthehate

A post shared by Jason Aldean (@jasonaldean) on Oct 2, 2017 at 1:17am PDT

Now words other than I'm lucky to be alive… prayers for those who lost people they love

A post shared by Chris Young (@chrisyoungmusic) on Oct 2, 2017 at 3:42am PDT

Praying for everyone here in Vegas. I witnessed the most unimaginable event tonight. We are okay. Others arent. Please pray.

— Jake Owen (@jakeowen) October 2, 2017