The number of detainees on hunger strike at Guantanamo has nearly doubled since last week, with at least two prisoners hospitalised due to dehydration, officials at the military prison said.
Captain Robert Durand, Guantanamo communications director, confirmed on Tuesday that 24 prisoners were on hunger strike, up from 15 since March 11, AFP reported.
However, he rejected claims that the majority of detainees were involved in a more widespread protest.
"Today, Tuesday, March 19, 2013, we have 24 hunger strikers, with eight on internal feed," he said. "The reports of hunger-strike-related deteriorating health and detainees losing massive amounts of weight are simply untrue."
In recent weeks, lawyers returned from the US base in Cuba where the prison is located with accounts of clients weak from hunger and an angry standoff with guards.
The military had said no more than a handful of prisoners met the definition of being on hunger strike, which includes missing nine consecutive meals.
That figure rose to 14 on Friday, and then grew by seven over the weekend.
It has become the largest and most sustained protest at Guantanamo in several years, but Durand insisted there is no evidence to support reports of a strike involving most of the 166 men held there.
"The detainees certainly have the support of one another," Durand said on Monday. "But if it was 166, I would tell you it was 166. I don't have a reason to lowball or pad the numbers.''
A prisoner from Yemen, Yasein Esmail, told his attorney that he lost about 15 kg after striking for 29 days and was struggling to keep his balance, according to notes taken by the lawyer, Washington-based David Remes, during a March 5 visit.
"Many of the detainees are desperate," Esmail told Remes. "They feel like they're living in graves."
Omah Farah, from the Center for Constitutional Rights (CCR), said several prisoners in Camp 6 where there are 130 prisoners had lost between 18 and 22 kg and most had lost between 9 and 13 kg.
Farah accused camp authorities of seeking to downplay the strike, which began on February 6 to protest searches carried out by prison guards.
Detainees have accused guards of "desecrating" Qurans during the searches.
Camp officials have strongly denied any mistreatment of the religious books.
Another apparent factor in the protest is the fact that the US has largely stopped transferring and releasing prisoners because of security restrictions imposed by Congress and the administration of President Barack Obama.
Durand said there had been no changes in the way searches are conducted.
He said Qurans are searched for contraband by Muslim translators, not guards, and are treated in a respectful way.
The protest is simply a way to attract attention, he said.
"They have sort of fallen out of the public view and most of the legal issues have been settled," Durand said. "If you want to burst back into the media then you have to start complaining about either Quran abuse or detainee abuse or deteriorating conditions."
Guantanamo prison was opened in 2002 to house prisoners rounded up in the so called War on Terror waged by the President George Bush administration following the 9/11 attacks.