VICKSBURG, Miss. (AP) -- Three Warren County Jail prisoners required treatment at a hospital following a weekend fire that authorities said was deliberately set.

The Sunday night incident, in which two mattresses and a blanket were set afire, forced the evacuation of 66 inmates. Sheriff Martin Pace declined to identify the three inmates, who were treated for smoke inhalation at River Region Medical Center and released, or the prisoner he believes is responsible for the fire.

''We won't be releasing any names of those who were treated and will not identify publicly the inmate we will charge until investigators meet with the district attorney to make a formal charge,'' Pace said Tuesday.

Pace said inmates were evacuated from the jail's second floor, where the blaze was set. Of those, 15 were temporarily moved to Issaquena County and the rest were taken to a Vicksburg Police Department holding cell. They were later returned to the jail.

Pace said jail security was not breached in the three-story jail, the original part of which dates to 1906, and there was no structural damage. The jail houses about 300 inmates.