As many as 2,800 inmates of a South Texas prison will be moved to other facilities one day after several hundred prisoners took over part of a federal prison in Raymondville, Texas. The Willacy County Correctional Center is now “uninhabitable due to damage caused by the inmate population,” U.S. Bureau of Prisons spokesman Ed Ross said in a statement.

Willacy County Sheriff Larry Spence refused to discuss the details of the negotiations, but confirmed no hostages were involved and there were few injuries. Authorities said approximately 800 to 900 other prison inmates chose not to participate in the uprising. The inmates are “low-level offenders” who authorities say are primarily illegal immigrants.

Inmates rioted Friday, complaining about such issues as poor medical conditions and overcrowding. The incident began at breakfast, when several inmates refused to leave their cells. By 12:15 p.m., the facility was on lockdown.

“There’s been some shots fired. Guards on top of the tower were firing. What they were using as ammunition, I have no idea,” Spence told the Valley Morning Star.

“It’s calm right now, but with caution,” the sheriff added. “It could explode any minute.”

Prisoners set fire to three of the 10 prison tents. The prison facility is comprised of 10 Kevlar domes that were constructed in 2006.

Inmates who spoke to the ACLU complained of guards using solitary confinement to punish ill prisoners, delayed medical care, cramped living conditions and interference by prison officials with inmates attempting to speak to lawyers.