Images from inside the military prison at Guantanamo Bay give an insight into the heavy-handed tactics the United States is using to force-feed prisoners.
With 104 of the 166 prisoners in the US prison beginning a hunger strike in February in protest at conditions, the force-feeding programme has been under the spotlight.
The images, released by the US, show the room where inmates are strapped into a chair so they can be fed through a straw inserted through their nose into their stomach in a procedure called "enteral feeding".
Inmates are force-fed under only certain conditions.
If they refuse nine successive meals or if their body weight drops significantly, they are offered a twice-daily can of a nutritional supplement. If they refuse that, guards shackle them into the chair by their arms, head and feet, and a nurse inserts the tube up the nose, down the back of the throat and into the stomach.
While most prisoners are taken to designated "feeding cells", some are fed at the Cuban base's detainee hospital, where the photographs were taken. They are asked to point to one of six happy or sad faces on a card to indicate their discomfort level.
The Daily Mail reported that the process left prisoners in pain.
It said Samir Naji al Hasan Moqbel, a Yemeni who has been on hunger strike since February after 11 years at Guantanamo, described how he wanted to vomit when the feeding tube was first stuck up his nose.
"There was agony in my chest, throat and stomach," he said.
Ahmed Zuhair, a 47-year-old former inmate, described how four years of being regularly strapped to what he dubbed the "torture chair" had damaged his back and Nasal passages.
The Daily Mail said Zuhair, a Saudi former sheep trader who was never charged with any crime during a seven-year stretch at Guantanamo which ended in 2009, said his nose would bleed during each force-feeding. He claims he would be forced roughly into the chair and left there much longer than the official two-hour maximum. "The pain from each force-feeding is so excruciating that I am unable to sleep at night because of the pain in my throat," he said in a sworn statement.
US military officials have acknowledged a "forced cell extraction team" was repeatedly used to move Zuhair when he refused to walk on his own to where hunger striking detainees were fed.
A military spokesman said the feeding tubes were lubricated and prisoners were offered anaesthetic to prevent long-lasting damage.