Updated

"High-value" detainees at the Guantanamo detention camp in Cuba are requesting the erotic book series "Fifty Shades of Grey" as reading material, making the novels even more popular than the Koran in the prison, a U.S. congressman claims.

Reuters reports Rep. Jim Moran, R-Va., toured Camp 7, the top-security facility that holds more than a dozen "high-value'' prisoners, including five men charged with plotting the Sept. 11 attacks, with a Congressional delegation last week.

"Rather than the Koran, the book that is requested most by the (Camp 7 detainees) is 'Fifty Shades of Grey.' They've read the entire series,'' Moran said according to Reuters. "I guess there's not much going on, these guys are going nowhere, so what the hell.''

A military spokesman says the prison does not discuss the detainees held in Camp 7 except for in the most generic of terms.

Reuters reports Guantanamo librarians have said in the past that they screen reading material for sexual content.

Reuters contributed to this report