JACKSON, Miss. — A gang fight in a prison for illegal immigrants quickly escalated into a riot involving as many as 300 inmates, some lashing out with sticks or homemade knives as the uprising spread through the sprawling prison, a sheriff said.

A guard was beaten to death and at least 20 other people were injured. The riot began Sunday afternoon and lasted into the night, with inmates dragging mattresses and wood to an outdoor recreation yard to set ablaze, Adams County Sheriff Chuck Mayfield said.

While law enforcement agencies from several counties waited outside the Adams County Correctional Facility in Natchez, authorities inside responded with tear gas and tactical units. They slowly corralled the inmates into a yard and searched them. By 2:45 a.m. Monday, all prisoners were back in their cells and the prison was locked down.

Mayfield said it’s not clear if the violence began within a gang or it was a dispute between rival groups, but “once it got started, it spread like wildfire.”

“They had makeshift weapons, broom handles, mop handles, anything they could pull apart, trashcan lids for shields, anything they could grab,” Mayfield said.

The prison holds nearly 2,500 low-security inmates, with most serving time for coming back to the United States after being deported, said Emilee Beach, a prison spokeswoman. Some of the inmates have also been convicted of other crimes, but their offenses were not immediately clear.

The facility is owned by Nashville, Tenn.-based Corrections Corporation of America, one of the nation’s largest private prison companies.

Catlin Carithers, who joined CCA in 2009 and was a senior correctional officer, was killed during the mayhem, Mayfield said.

“He liked protecting people,” Carithers’ cousin, Jason Clark, told The Associated Press.

Carithers was engaged to be married and excited about a recent promotion that took him off the weekend shifts. He had been trained in recent years as part of the prison’s special response team and was called into work Sunday to help with the uprising, Clark said.

More than two dozen officers were held hostage or were trapped at some point, the sheriff said. At least 17 prison employees were treated for various injuries and three inmates were hurt. The sheriff said the inmates hurt each other, with one getting stabbed and another had broken ribs.

Bill Chandler, executive director of the Mississippi Immigrants Rights Alliance, said his group has gotten complaints about the facility in the past year, mostly from people saying they weren’t getting adequate health care.

Frank Smith, who runs the online prison watchdog group Private Corrections Working Group, said those kinds of conditions that usually trigger a riot.

“The big problem is CCA tries to cut corners in every possible way. They short-staff, they don’t fix equipment, and things just get more and more out of control, and that’s what leads to these riots. It’s just about maximizing short-term profits,” Smith said.