The military claim disputed allegations that nearly half the 500-plus prisoners are on hunger strike in Guanatamo. A military spokesman also denied charges that it has been beating up and otherwise abusing prisoners.
Some detainees have been fasting since 8 August and nine have been hospitalised but are in stable condition, Army Colonel Brad Blackner said.
"We continue to monitor them 24 hours a day. We continue to offer them water and food," Blackner said on Thursday. "The number (of prisoners on hunger strike) is nowhere near 200."
Most of some 500 detainees from more than 40 countries have been held more than three and a half years without charge or access to lawyers. One of the demands of the strikers is that they be charged and brought to trial, or freed.
Most were captured in the Afghanistan war, suspected of ties to al-Qaida or the ousted Taliban regime.
The military's account conflicted with Wednesday's report from the New York-based Centre Constitutional Rights that 210 prisoners were refusing food and that some are threatening to starve to death unless they are put on trial or released. The centre said one detainee even wrote a will before starting the hunger strike.
The detainees are angry because the US military allegedly reneged on promises to bring the prison into compliance with Geneva Conventions if detainees ended a June-July hunger strike that involved up to 200 of the 500-plus men from some 40 countries held at the base, the centre said.
After news of that hunger strike came from a freed detainee, the military said only 52 prisoners were not eating.
Blackner also denied the centre's claim that at least three detainees were abused by the military's Extreme Reaction Force.
"If the events ... actually happened I would know about it and I haven't heard anything about 'beating' or 'abusing' or throwing of a refrigerator," Blackner said.
Lawyers accuse the military of lying about the detainees.
The strike is the result of prisoners "who have grown desperate after more than three years of constant deceit. The military has lied to the prisoners over, and over, and over again," said Clive Stafford Smith, a British lawyer representing several detainees.
In another statement on Thursday, the Centre for Constitutional Rights said the Department of Defence "has continued to resist the efforts of counsel to meet promptly with their clients participating in the hunger strike".