WLBT has been told SWAT Teams have entered the Adams County Correctional Facility and can be seen with guns drawn walking along the roof the facility.
The riot has resulted in one fatality.
A spokeswoman for the Adams County Sheriff's Office Emily Ham confirmed Sunday evening that a guard died while being transported to a hospital. She said Corrections Corp. of America, the prison's private operator, is working with law-enforcement authorities to bring the disturbance under control.
Several other employees have been injured during what is being called an "an inmate disturbance" at a southwest Mississippi prison.
A small fire was started earlier in the courtyard of the prison.
Adams County Sheriff Chuck Mayfield tells the Natchez Democrat there are still prison guards inside the facility.
CCA said in a news release that the disturbance began at around 2:40 p.m. CDT Sunday.
The prison says five employees and one prisoner were taken offsite to be treated for injuries. There are several other people being treated for injuries at the facility.
At times you could hear what appeared to be tear gas guns being fired and tear gas smoke rising above the prison.
The prison says "the disturbance has been contained within the secure perimeter of the facility, with no threat to public safety."
The 2,567-bed prison houses federal inmates.
The company said the cause of disturbance is pending investigation.