KABUL, Afghanistan -- Doctors Without Borders released an internal report Thursday describing the deaths of patients and its workers in a hospital in northern Afghanistan that was bombed by U.S. forces last month.

The international medical charity, known by its French acronym MSF, also said wounded Taliban fighters were being treated in the hospital, but there were no armed men or fighting in the area at the time.

The charity confirmed that U.S. forces had the exact coordinates of the clinic before launching an aerial assault on Oct. 3 that killed 30 people, including doctors and patients.

The bombing lasted for more than an hour, during which time "patients burned in their beds, medical staff were decapitated and lost limbs, and others were shot by the circling AC130 gunship while fleeing the burning building," the report says.

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"We lost our ability to treat patients at a time when we were needed the most," MSF general director Christopher Stokes said in a statement posted to the charity's website. "We were forced to leave patients to die on the operating table and others burning in their ICU beds."

According to the report, a hospital worker was decapitated by shrapnel while running for safety. Shrapnel also killed a patient in a wheelchair who was trying to escape from the hospital's inpatient department.

Witnesses in the report described other people running while on fire and falling to the ground unconscious.

"MSF doctors and other medical staff were shot while running to reach safety in a different part of the compound," the report says.

President Obama apologized for the attack. The U.S. military said the airstrike, requested by Afghan forces, was a mistake.

But Stokes said "a mistake is quite hard to believe and understand." The report, based on interviews with around 60 MSF staff, confirmed earlier accounts by the group.

MSF treats anyone wounded in armed conflict without regard to political affiliation, Stokes said. He said a "no weapons" policy was upheld at the hospital in the northern city of Kunduz.

Acting Afghan Defense Minister Masoom Stanekzai, in a recent interview with The Associated Press, said the hospital was being used as a command center for Taliban militants who seized the city on Sept. 28. The militants held Kunduz for three days before being driven back by a government counteroffensive.

At least two U.S. and NATO military investigations into the hospital bombing are underway, though it is unclear when the results will be made public.

Afghan President Ashraf Ghani has so far ordered at least two reports, but one is only focused on what led to the Taliban takeover of Kunduz, according to Western and Afghan officials familiar with its content.

The MSF report says the group received a call on Oct. 1 from a U.S. official in Washington asking if there were a "large number of Taliban 'holed up' in the Kunduz clinic or any other MSF locations." Stokes said the official was with the Defense Department.

The official was told the hospital was "full of patients including wounded Taliban combatants," the report says. Stokes said there was no subsequent contact with U.S. officials ahead of the bombing, but the call was not unusual given the fighting in Kunduz at the time.

Stokes said the official's question "seems to suggest they believed there were a group of Taliban holed up that weren't only patients in the hospital."

MSF has called for an independent investigation into the bombing. Many of the people killed were women and children, as well as doctors and nurses, Stokes said.