New legal filing says plan to continue feeds at night during holy month will be dangerous for health of detainees

Lawyers acting for four detainees on hunger strike at Guantánamo Bay have accused the US government of preparing to operate a "force-feeding factory" in the camp during the holy month of Ramadan.

In a new legal filing lodged with a federal court in Washington, lawyers for the men argue that the feedings during Ramadan will lead to mass use of restraint chairs, require hundreds of staff to administer and could be dangerous for the health of detainees. "If this can even be achieved, Guantánamo Bay will become a veritable force-feeding factory," the lawyers write.

In response to earlier legal challenges, the US government has refused to suspend force feeding through tubes directly into the stomachs of detainees during Ramadan. Some 45 men out of 106 currently on hunger strike are being enterally fed in this way.

The government defends the practice by saying it is "humane, high-quality medical care to preserve life and health". When Ramadan starts on Monday, the daytime fast will be respected if possible and force feedings will only take place before dawn or after sunset. However, the government has added a proviso, implying that daytime force feeding might be necessary, given "any unforeseen emergency or operational issues".

Four hunger strikers are challenging that equivocal plan in the courts: Shaker Aamer, a British resident who has been held without trial in Guantánamo for more than 11 years, Ahmed Belbacha, Nabil Hadjarab and Abu Wa'el. Their lawyers, Cori Crider of the human rights charity Reprieve and Jon Eisenberg, argue in the new court filing that involuntary feeding at night will have a drastic impact.

They point out that force feedings are normally carried out twice a day, with the procedure taking up to 30 minutes and the detainee then placed in a "dry cell" without water for up to two hours, in an attempt to stop them vomiting. Between sunset and sunrise – which on the first full day of Ramadan will occur at 7.44pm and 6.28am at the US naval base in Cuba – there will be just 10 hours and 44 minutes available to camp wardens to carry out two force feedings each of 45 detainees involving an hour in total of feeding time and up to four hours of observation per man.

The filing suggests that could require "dozens of restraint chairs and hundreds of staff. The fasting detainees, who may not take water during the daylight hours of Ramadan, will be spending up to four more nighttime hours without access to water as well as being under physical restraint, putting them at substantial risk of dehydration and sleep deprivation".

The hunger strike was launched in February, as a protest against the legal limbo in which many of the 166 detainees at Guantánamo find themselves and against President Obama's failure to honour his 2008 promise to close the camp. In May, Obama said he would renew efforts to shut Guantánamo down, lamenting that it had "become a symbol around the world for an America that flouts the rule of law".

The four hunger strikers are appealing to the US court for the District of Columbia to ban force feeding at Guantánamo generally, and during Ramadan specifically. Their lawyers argue that the practice prolongs their indefinite detention, which is in itself a human rights violation.

The filing notes that the US government sees force feeding as necessary to prevent detainees "laying waste to their bodies". But it counters that their indefinite detention is "laying waste to their souls".