Hundreds of prisoners at the US-run Bagram jail in Afghanistan are refusing basic privileges to protest about their basic rights, officials say.
Inmates have refused to participate in a project which allows prisoners to talk to their families via video phone, the Red Cross says.
The US military considers inmates there to be "unlawful combatants" who can be held for as long as deemed necessary.
It is estimated that about 600 inmates are being held at the prison.
The prisoners are reported to be protesting against what they say are a lack of basic rights such as access to lawyers or independent reviews of their status.
The Washington Post newspaper recently reported that prisoners in Bagram have been protesting against their "indefinite detention".
The protest is said to have started at the beginning of July.
"During our last regular visit at the beginning of July, the detainees told us they did not want to participate in the family video phone call and family visit," Jessica Barry, a spokeswoman for the International Committee of the Red Cross (ICRC) told told the AFP news agency.
The prisoners are also reported to have declined family visits and outside recreation time.
The ICRC is the only humanitarian organisation which has access to the prison.
Last month the BBC uncovered allegations of abuse and neglect at the detention facility.
A number of former detainees alleged they had been beaten, deprived of sleep and threatened with dogs at the base.
Of 27 ex-inmates the BBC spoke to around the country over two months, only two said they had been treated well.