The Justice Department announced Thursday that it will start phasing out the use of private prisons for the federal prison population.

Deputy Attorney Sally Yates announced the move in a Thursday memo, and said privately run prisons aren't as safe or effective as government-run correctional facilities.

In the memo, Yates informed Justice Department officials they should decline to renew or attempt to reduce the scope of existing contracts with the goal of "reducing — and ultimately ending — our use of privately operated prisons."

"They simply do not provide the same level of correctional services, programs, and resources; they do not save substantially on costs; and as noted in a recent report by the Department's Office of Inspector General, they do not maintain the same level of safety and security," Yates wrote.

A report last week from the Justice Department's Inspector General was critical of privately operated correctional facilities, and said they have more safety and security issues than those run by the federal Bureau of Prisons.

There are currently 13 privately run facilities in the country. According to Yates, they won't close overnight, but the Justice Department will instead review their contracts as they come up for renewal over the next five years.

The announcement comes on the heels of a Mother Jones investigation of a private prison run by the Corrections Corporation of America in Louisiana. That investigation found serious deficiencies in staffing and security at the Winn Correctional Center in Winnfield, as well as a higher rate of violence than the prison reported.

As of December 2015, private prisons incarcerated about 22,600 federal inmates.