Inmates at the federal prison camp in Otisville, N.Y., were stunned by what they saw at the chapel library on Memorial Day — hundreds of books had disappeared from the shelves.

The removal of the books is occurring nationwide, part of a post-September 11 federal directive intended to prevent radical religious texts, specifically Islamic ones, from falling into the hands of violent inmates.

Three inmates at Otisville, about 80 miles north of Manhattan, filed a lawsuit over the policy, saying their Constitutional rights were violated. They say all religions were affected.

“The set of books that have been taken out have been ones that we used to minister to new converts when they come in here,” inmate John Okon told a judge last week.

Okon said it was unfortunate because “I have really seen religion turn around the life of some of these men.”

Assistant U.S. Attorney Brian Feldman told U.S. District Judge Laura Taylor Swain that prison libraries limited the number of books for each religion to between 100 and 150 under the new rules.

Mr. Feldman said the removal order stemmed from an April 2004 Department of Justice review of the way prisons choose Muslim religious services providers.

Mr. Feldman said the study was made out of a concern that prisons “had been radicalized by inmates who were practicing or espousing various extreme forms of religion, specifically Islam, which exposed security risks to the prisons and beyond the prisons to the public at large.”