A large number of prisoners at Guantanamo Bay are on hunger strike, according to their attorneys, protesting their mistreatment and abuse by US military authorities and the Obama administration’s refusal to repatriate prisoners who have been cleared for release.

Information about the hunger strike is extremely meager because of military censorship. However, on Friday 51 lawyers representing half of the 166 remaining prisoners at the US base in Cuba issued a statement of protest in the form of a letter to new US secretary of defense, Chuck Hagel.

They expressed “urgent and grave concern about a mass hunger strike taking place at the prison, now in its second month” and sought Hagel’s intervention in “a serious threat to the health and life of detainees.”

The letter said the lawyers have received “alarming reports” of prisoners losing “over 20 and 30 pounds” and said that “at least two dozen men have lost consciousness due to low blood glucose levels.”

Military officials gave lower figures for the protest, saying that 14 prisoners were refusing food, and six were being force-fed. Force feeding entails brutal violence to insert the tube through the nose, and is tantamount to torture. One of the six being force-fed has had to be hospitalized.

The majority of Guantanamo prisoners are held in Camp 6, a lower-security facility whose inmates are classified as “compliant.” These include a large group, nearly half, who have been officially declared no threat to the United States, but have been denied repatriation because of unstable political conditions in their home countries. Most of these are Yemenis.

The International Committee of the Red Cross, the only outside group given regular access to the Guantanamo prisoners, last visited the facility February 18-23. The group never criticizes prison authorities, but it acknowledged that the hunger strike is taking place. It issued a statement saying, “The ICRC believes past and current tensions at Guantanamo to be the direct result of the uncertainty faced by detainees.”

Press reports said the hunger strike was triggered by searches in Camp 6 in which guards looked through or confiscated Korans. A Pentagon official said that guards are forbidden to touch the Koran, and such searches are delegated to cultural officers, most of whom are Muslims.

The lawyers for the prisoners said the Guantanamo authorities have deliberately concealed acts of repression, including the firing of rubber pellets into a recreation yard used by prisoners, and a request by prisoners to turn their Korans back to the US military because they couldn’t keep them secure in their own possession.

A Reuters report said a photographer who had taken pictures of protest signs held up by prisoners had the photos deleted by military authorities.

One military defense attorney, Army Captain Jason Wright, told the Miami Herald about the condition of his Afghan client, Obaydullah, about 30 years old, who has been living on water or honey water for weeks.

“I was shocked. He’s lost at least 15 pounds,” said Wright. “He told me that detainees were passing out almost by the day. He conveyed that a detainee recently fell down and was in need of medical attention and it took several minutes for the other detainees to actually flag down a guard.”

Earlier this month, more than a dozen lawyers for Guantanamo prisoners filed a protest with the detention center commander, Rear Adm. John Smith, describing the initial stages of the hunger strike, including “men coughing up blood, being hospitalized, losing consciousness, becoming weak and fatigued.”

The attorneys cited indications that the prison guards have become far more aggressive and intrusive over the past four months. One military staff lawyer at the prison reportedly told a hearing last month that Army guards who replaced Navy sailors recently have adopted new and tighter search criteria, confiscating books, legal documents and even a photograph of the Grand Mosque in Mecca, an object of religious devotion to Muslims.