(CNN) -- More prisoners have joined a hunger strike at the U.S. detention facility in Guantanamo Bay, Cuba.
The number of suspected terrorists involved has risen to 24 as of Tuesday, Pentagon spokesman Lt. Col. Todd Breasseale said.
There were 14 last week. U.S. military officials deny detainee lives are in danger.
Breasseale said eight require feeding tubes that are administered through the mouth.
There are 166 suspected terrorists being held at the detention facility.
"The medical staff continuously monitors and provides outstanding medical care to detainees in our custody," Breasseale said.
"The health and well-being of detainees is their primary mission and they take this duty as seriously as they would a duty to treat our own service members or any patient in their care," he said.
Beginning last year through mid-February, between five and six detainees started and stopped hunger strikes, Breasseale said.
But the numbers grew after lawyers for some of the detainees drew attention to conditions at the facility, Breasseale said.
"The reports of hunger-strike related deteriorating health and detainees losing massive amounts of weight are simply untrue," Breasseale said.
David Remes, a Washington-based lawyer who represents 15 detainees at Guantanamo, said his February visit shocked him.
"I think every one of the clients I saw had lost 30 pounds or more when I was there," Remes said. "They were weak and chilled."
Remes said two of his clients were unable to meet because they were too weak from their hunger strike. He said he knows that at least six of his clients are participating.
He said his clients told him the strikes were "the last straw" in response to what was described as more intrusive treatment in recent months.
For instance, his clients were unhappy with an early February search of detainee personal items and an intent to search Korans, something that had stopped in 2006.
"It is incredibly insulting to Islam as far as these men are concerned, most of whom are very devout Muslims, and it seems to be solely to demonstrate the administration's (Guantanamo commanders) power and not on a justification basis," Remes said.
He said checking Korans pushed them toward the hunger strike but other incidents stoked their anger.
In one last January, a guard in a watch tower shot at a group of detainees who had gathered to complain about another issue.
"Rarely does what is relayed to defense counsel by the detainees, which some members of the defense council then dutifully take to the press, match with reality," Breasseale said in response.
"This is another example of myth-making by the detainees. Only after detainees attempted to climb the fence and then hurled stones at the guards in the tower, was a single shot fired and only after reasonable cause, was a cell ever searched," according to Breasseale.
Last Thursday, Remes and more than 50 other lawyers who represent detainees at Guantanamo wrote to Defense Secretary Chuck Hagel, complaining that they have been receiving reports by detainees that the, "health of the men has continued to deteriorate in alarming and potentially irreparable ways."
The letter asks Hagel to meet with the lawyers to work out a solution.