SPRINGFIELD – Security is being undermined at Illinois’ prisons because of overcrowding and the need for space, a prison watchdog group said Thursday after state officials confirmed that six medium-security prisons would be using gymnasiums to temporarily house extra inmates.

Extra beds are being set up in the facilities in preparation for the closing of the women’s prison in Dwight, according to the main prison-employees’ union. A spokeswoman for the Department of Corrections said officials are preparing a half-dozen prisons but declined to say whether they’re linked to the Dwight shutdown or how many low-level offenders would be housed in the interim space.

The temporary housing poses safety concerns for a prison system that has 49,000 inmates in space designed for 33,000, combined with too few employees to watch them, said John Maki, executive director of the John Howard Association, a not-for-profit group that tracks the state’s prison system.