Prison officials were trying to get control over a riot at a federal correctional facility in southern Texas, after as many as 2,000 prisoners became involved in the violence late Friday.
The disturbance began Friday morning when inmates at the Willacy County Correctional Center refused to report to work or appear for breakfast, according to Issa Arnita, a spokesman for Management & Training Corp., a private company that runs the prison.
Arnita said some of the prisoners were protesting medical services at the facility.
The prison, located in Raymondville, about 40 miles northeast of the border town of McAllen, houses "deportable individuals" who have been convicted of federal crimes and are eligible to be deported once their prison terms are up, according to Bureau of Prisons spokesman Ed Ross.
Federal prison officials are "monitoring the situation" at the Willacy County facility, which houses about 2,880 inmates, Ross said.
The facility was locked down at 12:15 p.m., and local sheriff's deputies were called in as a precaution.
Soon after that, several inmates broke out of their housing units and went out into the recreation yard. About 2,000 prisoners are believed to have joined the protest, Arnita said. Officials said inmates set fire to three of the 10 prison tents, causing minor damage, the Valley Morning Star reported.
Officers deployed tear gas, and two officers and three inmates sustained minor injuries, Arnita said. All five were treated on site. About 1,000 other inmates housed in a separate building were not involved, officials said.
Officials said they had called in "disturbance control teams" from nearby prisons as well as additional law enforcement officers, who have set up a security perimeter around the prison. All staff members have been accounted for.
"We are attempting to speak with the offenders to bring a peaceful solution to this incident," Arnita said late Friday night. "The facility remains secured with no danger to the public."
Earlier in the day, the riot prompted school officials to place three nearby schools on lockdown.
According to a June 2014 report by the American Civil Liberties Union, most of the living quarters at Willacy County Correctional Center consist of Kevlar tents, equipped with bunk beds, that house about 200 men each.
"Prisoners reported severely overcrowded and squalid living conditions" including frequent sewage leaks and inadequate medical treatment, the report said.
A prisoner revolt in February 2014 resulted in injuries to prisoners and prompted officials to deploy 30 sheriff's patrol cars to the facility as a "defensive measure," the report said.