A rare letter has been published from a Guantanamo Bay detainee, belonging to the Uighur ethnic group in China, outlining harsh conditions.
The Uighur men have been in detention for six years
Abdulghappar Turkistani, 35, is one of a group of 17 Chinese Muslims who have been held at the US camp for six years.
Lawyers for the group say they have been approved for release by the US authorities but cannot return to China for fear of persecution.
Efforts to find a country to take the group have so far come to nothing.
The Uighurs, who are ethnic Turkic Muslims, come from Xinjiang province, where China meets Central Asia.
Uighur activists are seeking autonomy from China and there are sporadic outbreaks of violence in the province. Beijing accuses the activists of links to international terrorism networks.
Mr Turkistani wrote the letter on behalf of his fellow Uighurs in December. US authorities recently cleared it for release.
In it he described the small, window-less cells where inmates were kept at the detention centre's Camp Six.
Ethnically Turkic Muslims, mainly in Xinjiang
Made bid for independent state in 1940s
Sporadic violence in Xinjiang since 1991
Uighurs worried about Chinese immigration and erosion of traditional culture
"Being away from family, away from our homeland... being forbidden from the natural sunlight, natural air, being surrounded with a metal box all around, is not suitable for a human being," he said.
He had developed rheumatism and another Uighur was being force-fed twice a day after joining a hunger strike, he said.
Mr Turkistani said that the group - who were told that they would be freed by US military authorities in 2004 and 2005 - did not know why they were still being held.
"We fail to know why we are still in jail here," he said. "We are still in hope that the US government will free us soon and send us to a safe place."
His lawyer, Seema Saifee, said that the group were seeking resettlement in the US or Europe.
In the meantime, she said, they were being held in solitary confinement for 22 hours per day, with "hardly any means of communicating with each other".
A spokesman for the detention centre defended conditions at Camp Six, calling it a "a state-of-the-market detention facility".
Five Uighurs were freed from Guantanamo Bay in mid-2006 and sent to Albania.
About 275 inmates remain at the detention camp in Cuba.