FORT MADISON, Iowa (AP) — Iowa prison officials are facing renewed criticism from a union representing correctional officers following an attack by an inmate at the Iowa State Penitentiary in Fort Madison that left a staffer hospitalized.

Prison officials said in a news release that the inmate used a weapon in the Wednesday attack to strike the staffer several times. A statement later released by the union said the staffer was stabbed five times by an inmate wielding two 10-inch shanks.

Danny Homan, president of the American Federation of State, County, and Municipal Employees Council 61, says the inmate is associated with a white supremacist prison gang, and that prison officials have ignored staff warnings that attacks by inmates were planned.

A Corrections Department spokesman didn’t immediately return phone and email messages Wednesday seeking comment.