More than 150 doctors from the United States and Britain have written to President Barack Obama urging him to grant independent medical care to hunger-striking Guantanamo detainees.
A prominent US senator who visited the facility earlier this month meanwhile called for a reevaluation of force-feeding procedures at the military prison, saying current methods raise "ethical questions."
The hunger strike, which began more than four months ago, is meant to protest the inmates' indefinite detention at the facility even though more than half have been cleared for release.
The letter, published Wednesday in the Lancet medical journal, said it was "imperative for (the detainees) to have access to independent medical examination and advice, as they ask, and as required by the UN and World Medical Association."
"Without trust, safe and acceptable medical care of mentally competent patients is impossible," the letter said.
"Since the detainees do not trust their military doctors, they are unlikely to comply with current medical advice."
The group Physicians for Human Rights has repeatedly urged Obama to halt the force-feeding of detainees.
Of the 166 inmates held at the remote US military camp in Cuba, 104 are refusing food and 44 were being provided nourishment through nasal tubes as of Wednesday, said prison spokesman Lt. Col. Samuel House.
One has been hospitalized but is not in critical condition.
"Detainees' rights to make decisions about their own health must be respected," said Vincent Iacopino, the group's medical advisor.
"Force feeding not only constitutes inhumane and degrading treatment, but is a clear violation of medical standards, and must be ended immediately."
Democratic Senator Dianne Feinstein, who visited the facility on June 7, called for a change in force-feeding practices, which involve forcibly restraining inmates and feeding them through nasal tubes.
"I remain concerned that these policies are out of step with international norms, medical ethics and practices of the US Bureau of Prisons," she wrote in a letter to US Defense Secretary Chuck Hagel.
"I believe that the current approach raises very important ethical questions and complicates the difficult situation regarding the continued indefinite detention at Guantanamo," she wrote.
"I urge you to reevaluate the force-feeding policies at Guantanamo Bay and to put in place the most humane policies possible."
Obama last month renewed his pledge to shutter the prison, which was set up in the wake of the September 11, 2001 attacks to hold terror suspects captured on foreign battlefields.