Las Vegas Police Respond to Active Shooter Situation at Mandalay Bay & Nearby Country Music Festival

The Route 91 Harvest Country Music Festival in Las Vegas was marred by violence on Sunday when a gunman opened fire at the event.

Las Vegas Police have confirmed that they are investigating an active shooter situation at the Mandalay Bay Resort and Casino, next to where the outdoor festival was being held at the Luxor Hotel & Casino.

Several of the arists at the event took to Twitter to warn others about the shooting.

Jake Owen, who performed on Sunday evening at the three-day festival, took to Twitter later that night, writing, "Gun shots!!! Vegas. Pray to god. Love you guys. Love you Pearl."

Abbot told fans that all members of the Josh Abbot Band were safe, and that they had been evacuated. He added, "My fiancée is still in the room. They won't let me in but she's safe."

ET will continue to update this story as it develops.