Doctors writing in the venerated New England Journal of Medicine are calling on American physicians to speak out against the force-feeding of Guantanamo detainees, labelling the U.S. detention centre a “medical ethics-free zone.”

“Physicians at Guantanamo cannot permit the military to use them and their medical skills for political purposes and still comply with their ethical obligations,” the journal stated in an article posted Wednesday.

“Force-feeding a competent person is not the practice of medicine; it is aggravated assault. Using a physician to assault prisoners no more changes the nature of the act than using physicians to ‘monitor’ torture makes torture a medical procedure,” said the article, written by Dr. George Annas, Dr. Sondra Crosby and Dr. Leonard Glantz.

Guantanamo’s medical staff previously had been accused of violating their ethics for providing advice to interrogations teams at the prison.

The journal urges doctors to take action — by petitioning the Pentagon or Congress — and support Guantanamo’s military physicians who may be reprimanded if they reject orders to feed starving inmates.

The hunger strike is now in its fourth month and, according to figures provided by the Pentagon on Wednesday, 104 of the remaining 166 detainees are participating. Forty-three of those men are being tube-fed liquid nutrients while shackled to a restraint chair.

The journal’s criticism follows an April statement by the American Medical Association that said force-feeding detainees violates the “core ethical values” of the medical profession.

U.S. Marine Gen. John Kelly, the Southern Command chief who oversees Guantanamo’s prison, created a stir last week when he denied that the detainees were force-fed, calling it “Hunger Strike Lite.”

His comments followed those of U.S. President Barack Obama, who lamented the “force-feeding” of detainees, saying at his national security address: “Is this who we are? . . . Is this something that our Founders foresaw?”