Extra medical staff have been sent to the U.S. military prison in Guantanamo Bay to help address a hunger strike that has spread to nearly two-thirds of the detainees, authorities said Monday.

With the strike now entering its 12th week, President Barack Obama has faced fresh calls to honor his promise to close the prison at the U.S. base in Cuba, which holds 166 individuals captured as part of the “War on Terror.”

Some 40 U.S. Navy medical personnel, including nurses and specialists, arrived over the weekend, said Lieutenant Colonel Samuel House, a military spokesman at Guantanamo.

“The influx of personnel was planned several weeks ago as increasing numbers of detainees chose to protest their detention,” he said.

House said 100 of the 166 inmates are striking, a number that hasn’t changed since Saturday. Of those, 21 are receiving feeding through nasal tubes, the spokesman said, one more than on Saturday.

Five are hospitalized, he added in the statement, without specifying whether any were in life-threatening condition.

However, he told AFP that none were close to dying, officially denying allegations by British Guantanamo expert Andy Worthington, who wrote on his blog that four prisoners were “close to death” as a result of the strike, citing a “credible source inside Guantanamo.”

One of the at-risk detainees, Worthington said, was Khiali Gul, one of 86 prisoners cleared for release yet jailed indefinitely.

“Every day I expect to hear the worst. I am appalled that President Obama has done nothing, and continues to do nothing,” Worthington told AFP.

Lawyers for the detainees have said around 130 inmates are observing the hunger strike, more than officially acknowledged.

The rapidly growing protest movement began on February 6, when inmates claimed prison officials searched Korans in a way they considered blasphemous, according to their lawyers.

Officials have denied any mishandling of Islam’s holy book.

But the strike has now turned into a larger protest by prisoners against their indefinite incarceration without charge or trial over the past 11 years.

House said recently that while detainees have a right to protest, “it is our mission to provide a safe, secure and humane environment, and we will not allow our detainees to starve themselves to death.”

On Friday, the White House said it continues to closely monitor the hunger strikers and that Obama remained “committed to closing” Guantanamo.

“A fundamental obstacle to closing this detention facility ... remains in Congress,” White House spokesman Jay Carney said.


A ‘critical moment’

More and more critics have called for the immediate closure of the facility.

Among them is former chief prosecutor at Guantanamo, Air Force colonel Morris Davis, who warned that “unless President Obama acts soon, I believe it is likely one or more of the detainees will die.”

Andrea Prasow, senior counterterrorism counsel and advocate at Human Rights Watch, said “there has never been such a critical moment in the history of Guantanamo.”

“It’s an incredible crisis in the American government, both in terms of health and welfare of these men, but there are also very serious national security concerns should someone die in Guantanamo,” she told AFP.

“I think it will be perceived outside of the U.S. as the U.S. government’s responsibility.”

Senator Dianne Feinstein, a Democrat from California, wrote a letter to Obama asking the administration to “renew its efforts” to transfer out the 86 detainees who were cleared for such a move by U.S. military authorities.

She also called for the reassessment of the “security situation on the ground in Yemen, because is my understanding that 56 of the 86 detainees cleared for transfer are Yemeni.”

Obama imposed a moratorium on repatriating Yemenis held at Guantanamo in 2009 after a plot to blow up an airliner on Christmas Day was traced back to al-Qaeda’s Yemeni franchise.