Despite force feeding by the American military, several hunger strikers at Guantanamo Bay may be close to death, according to lawyers acting for the detainees.

The condition of two emaciated Yemeni hunger strikers who have been refusing solid food since August is causing particular concern. There are also fears for the life of a hospitalised Saudi prisoner.

The wife of a British resident and hunger striker, Shaker Aamer, visited the Commons last week to appeal to MPs for help. Aamer’s wife, 31, who lives in London with her four children and has asked for her name to be withheld, said: “This is the time to do something. My husband is not going to last.”

Aamer has been on hunger strike since November 2. Although he has lost weight, he is stronger than some other prisoners taking part in the protest at their detention without trial.

According to a report to be released tomorrow by the prisoners’ rights group Reprieve, the Yemenis, identified as Abu Bakah al-Shamrani and Abu Anas, are said by detainees to be gravely weak. Shamrani weighs only 70lb (5 stone).

Reprieve claims Camp Echo, which is comprised of isolation cells, has been turned into a “force feeding institution” away from other prisoners and its gravel path paved with concrete so the hunger strikers can be moved around in wheelchairs.

The military said last week the number of hunger strikers had declined to 22 after a peak at Christmas and that 17 were being fed by “tube”.

Lieutenant-Colonel Jeremy Martin, spokesman for Joint Task Force Guantanamo, declined to give the number of detainees in hospital and said the hunger strikers were “malnourished” but “clinically stable”. He denied their lives were at imminent risk.

The US law firm Paul Weiss, which represents three Saudi detainees, has received increasingly alarming weekly medical reports about the condition of one of them, who is in the camp hospital.

On a trip to Guantanamo last month, Paul Weiss’s lawyers were prevented from visiting the hospital and told their clients did not wish to see them. “We are concerned they may be in a life-threatening condition,” said one of the lawyers, Jana Ramsay. “They are normally glad to see us.”

The prisoners being force fed have a permanent tube in the nose, which descends to the stomach and is attached to another tube for feeding. If they do not rip it out, the US military say they are consenting to be fed even if the tube was inserted under duress.

Aamer was visited this month by his lawyer, Clive Stafford Smith, legal director of Reprieve. In “obvious pain”, he pulled his tube out of his nose so it could be examined. According to Stafford Smith, it was 43in long and was stained red from having been in Aamer’s stomach.

Aamer has vowed to continue his hunger strike until he is given a fair trial or released. He said in a statement: “The British government refuses to help me. What is the use of my wife being British?” He said he held the British government as well as the Americans “responsible for my death”.

Stafford Smith said the “inevitable spectre of a Muslim prisoner dying on Guantanamo soil will cause greater outrage than even the desecration of the Koran”.