A sheriff in Mississippi says a Marshall County prison guard has been severely injured by an inmate.

Sheriff Kenny Dickerson tells WREG-TV that the guard was attacked Wednesday night and airlifted to a hospital. News outlets report the sheriff’s office says the guard suffered severe head trauma. Dickerson says the guard was in stable condition as of late Wednesday night.

The sheriff’s office says that inmate and several others started a fire inside the prison and were burning items just before the guard was hurt. WMC-TV reports the fire has been contained and the prison has since been placed on lockdown.

Authorities didn’t immediately release the identities of those involved.