Prisoners at the Guantanomo Bay detention camp have now been on hunger strike for 100 days.
At least 102 of the remaining 166 prisoners at the facility are refusing food.
The strike started in February, with prisoners angry at a new system for restraining them, which they said was harsher than the previous one.
Claims that their Qurans were mishandled during inspection, which sparked the protest, were denied by the authorities.
The prisoners are being force-fed in order to keep them alive.
Inmates are restrained and a feeding tube is pushed through their nose and into their stomach - a practice the UN compares to torture.
Speaking to Al Jazeera, Dr Otmar Kloiber, Secretary General at the World Medical Association, said the force-feeding was "degrading and inhuman".