The body’s rules state one of 76 signatory states must sponsor an inquiry. But for one to get formally underway, it must be endorsed by the parties to the conflict, in this case the U.S. and Afghanistan. Neither country is likely to support such a move.

Liu added:

We ask signatory states to activate the commission to establish the truth and to reassert the protected status of hospitals in conflict. It is unacceptable that States hide behind ‘gentlemen’s agreements’ and in doing so create a free for all and an environment of impunity. 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. Today we are fighting back for the respect of the Geneva Conventions. As doctors, we are fighting back for the sake of our patients. We need you, as members of the public, to stand with us to insist that even wars have rules.

MSF’s demand for an investigation comes a day after General John Campbell, the senior-most U.S. commander in Afghanistan, told a Senate committee that the hospital was “mistakenly struck.” He said the decision to strike the hospital “was made within the U.S. chain of command.”

As my colleague David Graham pointed out, Campbell’s remarks were part of a evolving line on the airstrike in Kunduz, the city captured by the Taliban last week before Afghan government forced retook it.

Following the airstrike Saturday, a U.S. military spokesman said there might have been “collateral damage” to a nearby hospital, but there was no acknowledgment of hitting the facility. Then, Defense Secretary Ash Carter acknowledged the MSF hospital had been struck, calling it a “tragic” accident. Then on Monday, Campbell said Afghan forces had requested the airstrike. Finally, on Tuesday, Campbell acknowledged that while the Afghans had requested the strike, the final decision went up the U.S. military’s chain of command.

Here’s David’s account of the changing narratives:

To recap, the U.S. first speculated that there might be collateral damage; then said the strike had been an accident; then blamed Afghans; and now has admitted the final decision sat with U.S. officials. A certain amount of confusion is unsurprising—the fog of war makes it tough to immediately determine what happened. But it looks bad for the official story to keep changing, and it’s bad news that the blame is moving closer to the U.S.—especially as Doctors Without Borders argues the airstrike was a war crime. MSF says U.S. and Afghan officials were informed of the exact location of the hospital.

To add to those shifting narratives, The New York Times is reporting that Campbell now believes U.S. troops “probably did not follow their own rules in calling in the airstrike” that destroyed the MSF hospital because no U.S. or Afghan troops were in extreme danger.

The airstrike killed 10 patients at the hospital and 12 MSF staff.