MIAMI - Prisoners taking part in an expanding hunger strike at Guantanamo Bay leveled new complaints about their military jailers Wednesday as a team from the International Committee of the Red Cross made a fact-finding trip to the U.S. base in Cuba.

In an emergency motion filed with a federal court in Washington, lawyers say guards have refused to provide drinking water to hunger strikers and kept camp temperature "extremely frigid," to thwart the protest. A spokesman for the detention center denied the allegations.

"The reality is that these men are slowly withering away and we as a country need to take immediate action," said Mari Newman, a human-rights lawyer based in Denver, who was among those who submitted the motion.

They filed the petition after interviewing Yemeni prisoner Musaab al-Madhwani by phone Monday. He told them that guards were refusing to provide bottled water and telling prisoners to drink from tap water that inmates believe is non-potable. The lawyers say in their motion that the lack of drinkable water has "already caused some prisoners kidney, urinary and stomach problems," in addition to the health effects of the hunger strike.

Along with their motion, they submitted an affidavit from Dr. Stephen Xenakis, a psychiatrist and retired general, who believes that the hunger strike and lack of adequate drinking water "sets them up for gastrointestinal infections and a quick demise." The doctor also said the 34-year-old al-Madhwani suffers from post-traumatic stress disorder linked to his torture while in U.S. custody in Afghanistan and could be worsened by harsh conditions at Guantanamo.

The U.S. government has not filed a response to the motion. Navy Capt. Robert Durand, a spokesman for the prison, said prisoners are provided with bottled water and that the tap water is safe to drink.

"It's potable water. It's the same water I make my coffee with and that they make lunch with," Durand said. He also denied that there had been any change to the air conditioning settings inside the prison camps.

Accounts of the hunger strike have been in sharp conflict for weeks. Lawyers who have visited or interviewed their clients say a majority of the 166 men held at Guantanamo have joined the protest and some have lost significant weight and are at serious risk.

The military said that as of Wednesday, there were 31 men on hunger strike, up from 28 on Monday. Three men were at the hospital being treated for dehydration and 11 were being force-fed with a liquid nutrient mix to prevent dangerous weight loss.

A two-person delegation from the International Committee of the Red Cross that includes a doctor is at the base to assess the situation. They started a week earlier than planned because of the hunger strike, said spokesman Simon Schorno.

"The reality is that these men are slowly withering away and we as a country need to take immediate action."

Mari Newman,

a human-rights lawyer based in Denver