During an interview with WREX-TV in Rockford, U.S. Rep. Donald Manzullo said alleged terrorists at the detention center are "are really really mean people whose job it is to kill people driven by some savage religion."
In a statement Tuesday, Manzullo confirmed those were his words during the Sunday interview, but he said they have been misinterpreted.
Most prisoners at the U.S. naval base in Cuba come from Muslim countries or have Muslim surnames.
Manzullo said he never specified Islam and apologized for any misunderstanding stemming from his comments.
"The religion of these terrorists is indeed savage -- it is not the religion of Islam," he said. "I never once said that Islam is a savage religion. It is a false conclusion or assumption. These terrorists have perverted the peaceful nature of Islam for their own demented purposes."
The comments from Manzullo come as federal officials consider buying a prison in Manzullo's northwest Illinois district that will house some Guantanamo detainees.
Manzullo has objected to the plan because of safety concerns.
At least one advocacy group said Manzullo's comments are a clear attack on Islam.
"It is outrageous and very sad that a representative of the people would partake in an attack against a global faith," said Ahmed Rehab, a spokesman for the Chicago office of the Council on American-Islamic Relations. "He could have said, 'a savage ideology' or 'a savage interpretation' or any type of nuance that a politician like himself knows how to do."
Rehab said rhetoric surrounding the prison proposal has been promoting hysteria and fear of Muslims.
Quinn and Durbin, both Democrats, said selling the Thomson Correctional Center -- about 150 miles west of Chicago -- would bring thousands of jobs to the economically depressed rural area.
Officials from the Federal Bureau of Prisons and the Defense Department inspected the nearly empty facility Monday. It was built in 2001.