Lawyers for scores of terror suspects on hunger strike at the Guantanamo Bay jail must be told before detainees are force-fed, says a US federal judge.
Some 500 people remain incarcerated at the Cuban jail
District Court Judge Gladys Kessler also ordered the US government to give medical records going back a week before such feedings take place.
She said the US "can hardly be proud" of its conduct if it was true that the jail had been using brutal methods.
The US denies using inhuman treatment of foreign suspects in its Cuba prison.
The Pentagon says 26 out of some 500 prisoners are on hunger strike that started in August, but one human rights group puts the figure at more than 200.
Most of prisoners at the US naval base in southern Cuba have been held for more than three years without being charged.
Judge Kessler said the US must notify the lawyers at least 24 hours before force feedings begin and also provide information at least weekly until suspects are no longer being fed by force.
US says 26 detainees on hunger strike; pressure group Reprieve says about 150
US says hunger strikers are "clinically stable"; Reprieve says some are in "grave peril"
US denies Reprieve's claims force-feeding is being used deliberately to harm detainees
US says only doctors and qualified nurses carry out the procedure; Reprieve says guards do too
US says detainees are being treated in accordance with Geneva Conventions; Reprieve says there are beatings and incidents of the Koran being disrespected
She acted after the lawyers representing about a dozen of Guantanamo detainees made an emergency petition, expressing concerns over the health of their clients
The judge spoke of "deeply troubling" allegations of forced feedings in which US jail personnel were accused of inserting thick tubes through the detainees' noses and into their stomachs without anaesthesia or sedatives.
"If the allegations are true - and they are all explicitly, specifically and vigorously denied by the government - they describe the conduct of which the United States can hardly be proud," the judge wrote.
However, she denied the lawyers' request for immediate telephone access to their clients.
The ruling affected a group of detainees from Qatar, Saudi Arabia, Yemen and Afghanistan.