A senior Pentagon official says that Muslim captives at the detention center in Guantánamo Bay, Cuba, have hidden weapons inside their copies of the Quran, a claim the U.S. military has yet to substantiate.

“There have, in the past, been incidents of detainees storing contraband in their Qurans; items found have included improvised weapons, unauthorized food and medicine,” wrote William K. Lietzau, deputy assistant secretary of defense for rule of law and detainee policy.

He made the claim in a one-page letter dated April 1 to the Center for Constitutional Rights, a New York law firm. The firm wrote Secretary of Defense Chuck Hagel on March 14, seeking a meeting to discuss the ongoing hunger strike at the Guantánamo prison, which they said started over a Feb. 2 Quran search and grew to present “a serious threat to the health and life of detainees.”

Lietzau, responding for Hagel, offered a broad defense of Quran search policy and told the lawyers he was “aware of reports that many detainees are engaged in a hunger strike.”

The Miami Herald has been asking the military since mid-March to provide specific details, including photographs, of items found concealed in detainees’ Qurans. n light of the Lietzau letter, The Herald asked additionally for specific incident reports. No details have been provided.

A dispute over Quran searches has been the underlying issue of the hunger strike that lawyers for the captives say is more widespread than the military acknowledges. On Monday, Navy medical staff considered 42 of the 166 detainees to be weak enough or to have lost enough weight to be classified as hunger strikers. Eleven were getting tube feedings of nutritional supplements, the camps said, and no hunger strikers were hospitalized.

The figure of hunger strikers rose from 41 on Friday to 42 on Saturday and remained the same on Monday, said Navy Capt. Robert Durand, a spokesman.

Lawyers have proposed that, if the Pentagon cannot agree to stop having staff search Qurans, it should let the captives turn them in for safekeeping. Prison officials refuse. Durand said letting captives return their individual Qurans would amount to a concession of desecration.

Several defense lawyers were asked whether they had ever heard an allegation of captives hiding contraband in Qurans.

“They’re not going to desecrate their own Qurans,” said attorney David Remes, who met with several hunger-striking Yemeni detainees and likened a weapon hidden in the holy book to hiding “a saw in a birthday cake.”

Remes called the military’s claim “desperate, grasping at straws” surfacing weeks into complaints about the prison staff’s searching the captives’ Qurans.

“If they were searching and they had found any kind of weapon they certainly would’ve made that claim when the hunger strike began,” Remes added. “Either they made it up or it was so long ago it was irrelevant.”

In the past when contraband was found in prisoners’ cells — but not Qurans specifically — the details were documented in a database.

A review of leaked, classified U.S. military risk assessments covering detainee behavior from the prison’s opening until 2008 show the prison camps painstakingly recorded items seized from prisoners’ cells. Examples cited included a razor found inside a detainee’s legal materials, a flexi pen wrapped in toilet paper, food hidden under a mattress, a sharpened spoon, “a pen that had been reinforced with paper and string,” a cup adorned with drawings of planes striking the World Trade Center.