Doctors Without Borders called on President Obama to consent to its launch of an independent investigation into a U.S-attack on a hospital in Afghanistan, saying it would demonstrate America’s “commitment to and respect for international humanitarian law and the rules of war."

“Our patients burned in their beds. Doctors, nurses, and other staff were killed as they worked. Our colleagues had to operate on each other,” the organization’s Executive Director Jason Cone said in a New York press conference Wednesday. 

“Today we say: enough. Even war has rules," he added.

Cone also called on the interntional community to show more respect for the Geneva Convention’s laws on war-time acts.

Wednesday’s statements come as the non-governmental organization, known internationally by its French name Medecins Sans Frontieres or its acronym MSF, announced plans to activate the International Humanitarian Fact-Finding Commission to investigate the weekend attack, which killed 22 people. It’s the greatest loss of life in the organization’s history.

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But the commission has never been used and requires one of the 76 signatory states to sponsor an inquiry. Until now, Cone said governments “have been too polite or afraid to set a precedent.”

The group said it is awaiting responses to letters it sent Tuesday to all 76 countries that have signed Article 90 of the additional protocol to the Geneva Conventions, seeking to mobilize a 15-member commission of independent experts. In this case, the United States and Afghanistan -- which are not signatories -- must also give their consent to such a mission.

Pentagon spokesman Capt. Jeff Davis said Tuesday that the Pentagon did not have an opinion yet about whether it would support such an investigation.

He added that there will be results from the NATO investigation "soon."

Doctors Without Borders’ International President Joanne Liu told reporters Wednesday in a Switzerland news conference that the organization could not trust internal investigations by the U.S. military, State Department and NATO.

“It is unacceptable that States hide behind ‘gentlemen's agreements’ and in doing so create a free-for-all and an environment of impunity,” he said. “It is unacceptable that the bombing of a hospital and the killing of staff and patients can be dismissed as collateral damage or brushed aside as a mistake,” Liu added.

On Tuesday, Army Gen. John F. Campbell, the top U.S. commander in Afghanistan, said the U.S. authorized the airstrike in Kunduz.

“The hospital was mistakenly struck. We would never intentionally target a protected medical facility,” he added.

In a possible indication that the attacking aircraft was given an improper go-ahead to open fire on the hospital, Campbell said he is requiring that every U.S. service member in Afghanistan be retrained on the circumstances in which U.S. air power can be used.

"To prevent any future incidences of this nature, I've directed the entire force to undergo in-depth training in order to review all of our operational authorities and rules of engagement," he said. U.S. forces are authorized to engage in combat in Afghanistan under certain limited circumstances, such as self-defense, attacking al-Qaida or aiding Afghan forces in extreme situations.

Defense Secretary Ash Carter issued a statement promising a full and transparent investigation.

"We will do everything we can to understand this tragic incident, learn from it and hold people accountable as necessary," he said.

The airstrike occurred as Afghan forces were retaking Kunduz from the Taliban.

The Associated Press contributed to this report.