The hunger strike, which began earlier this year, involved more than 100 prisoners at its peak. Joe Raedle/Getty Images

Officials at Guantanamo Bay have implemented revised protocols for hunger strikes and force-feeding, according to a Justice Department letter obtained by Al Jazeera. The controversial military detention center keeps scores of detainees imprisoned, often without charge.

The move comes as officials at the base disclosed this week that they would no longer release new figures to journalists on a hunger strike that is currently underway. As of Monday, the last day Guantanamo officials released fresh numbers, 15 prisoners were protesting, up by two from the previous week. All of the hunger strikers were reportedly being force-fed.

According to the Justice Department letter, officials at the base revised their protocols for dealing with the hunger strike and force-feeding methods on Nov. 14 to “better focus on the adverse health effects of clinically significant weight loss on each individual detainee.”

But mystery surrounds exactly what those changes are. Navy Cmdr. John Filostrat, the prison spokesman, declined to disclose details about what exactly changed in the Standard Operating Procedure (SOP), or to answer any questions about why the changes were made. Filostrat said to do so would interfere with “operational security.”

The hunger strike, which began earlier this year and involved more than 100 prisoners at its peak, created headlines worldwide and helped pressure President Barack Obama into repeating a previously stated aim of shutting down the base. But critics continue to accuse his administration of doing too little to implement that goal.

The revisions to the SOP were disclosed in a letter, dated Nov. 21 and signed by Justice Department attorney Daniel J. Lenerz. The letter was submitted to the U.S. Court of Appeals for the Washington, D.C., circuit as part of a long-running lawsuit filed earlier this year by attorneys representing a group of Guantanamo prisoners who are seeking to halt the force-feeding of hunger strikers.

Officials also decided this week to stop giving out information on the constantly fluctuating number of hunger strike participants out of a belief that the information had been helping the protesters.

“Our policy is to no longer publicly issue the number of detainees who choose not to eat as a matter of protest at Guantanamo,” Filostrat said.

“Guantanamo allows detainees to peacefully protest, but will not further their protests by reporting the numbers to the public,” he said. “The release of this information serves no operational purpose and detracts from the more important issues, which are the welfare of detainees and the safety and security of our troops.”

Previously, authorities had sent out daily updates on the number of detainees involved in the protest, including figures on those who were being force-fed. In September, a decision was made to stop those announcements but still release relevant numbers when journalists specifically asked. Now even that information will not be released.