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NEW: 300 prisoners moved to federal prison, hundreds more to follow, statement says

Tear gas used to bring inmates under control, says company that runs the prison

CNN  — 

Federal prison officials are relocating nearly 3,000 inmates after about two-thirds of them broke out of their housing units during a lockdown at a prison in South Texas.

The prisoners at the Willacy County Correctional Center refused to take part in work duties on Friday and some inmates said they were unhappy with medical services, said Management & Training Corp., the private company that runs the prison, in a press release.

As of Sunday morning, more than 300 prisoners had been transferred to federal prisons.

We anticipate another few hundred inmates will be moved by the end of the day,” MTC spokesman Issa Arnita said in a statement. “This process will continue through the next week until all of the inmates have been relocated. Investigators will then thoroughly assess the damage and begin repair work. Initial assessments indicate significant damage to the plumbing and heating and cooling systems.”

The inmates have been cooperative during the relocation process, the statement said.

The inmates were put on lockdown but some broke out of their housing units, MTC said. About 2,000 prisoners went into the recreation area, though none breached the outer fences, MTC said.

Another 1,000 prisoners in another part of the facility were not involved.

With assistance from other law enforcement agencies and by using tear gas, officers got the prisoners under control, MTC said. Two officers and three inmates suffered minor injuries.

The offenders are mostly low-level custody inmates who are “criminal aliens,” MTC said. Willacy County is located in the southern tip of Texas.

CNN’s Janet DiGiacomo contributed to this report.