It has been called a war crime, and could be the subject of an international investigation — but the U.S. attack on a hospital run by Doctors Without Borders in Afghanistan is the subject of a tangle of accounts.
At least 22 people, including several of the charity's medical staff, were killed in Saturday's strike.
President Obama apologized to the aid group Wednesday, but only after the United States gave shifting explanations of why the airstrike was launched.
The Afghan government has tried to justify the attack, stoking further backlash. Doctors Without Borders says both countries knew what they were doing, because the hospital's location was well known.
Who to believe? Here's how the response unfolded.
The American military's first acknowledgment of the 2:15 a.m. attack came later that day, when Col. Brian Tribus, a spokesman for the U.S. coalition in Afghanistan, gave a vague statement that the bombing had targeted "individuals threatening with force" but "may have caused collateral damage to a nearby health facility."
Secretary of Defense Ash Carter noted in a separate statement that U.S. and Afghan forces and Taliban fighters had all been active in the area surrounding the hospital, and "we are still trying to determine exactly what happened."
The Afghan military was more direct, saying that the U.S. conducted the airstrike "against insurgents who were directly firing upon U.S. service members."
Doctors Without Borders did not immediately counter those accounts. But a spokesman for the charity said that "all parties to the conflict, including in Kabul and Washington, were clearly informed of the precise location (GPS coordinates)" of the hospital. The spokesman also noted that the bombing continued for a half hour after the group first informed military officials in both countries what was happening.
The group's president, Meinie Nicolai, recoiled at the U.S. description of the attack as "collateral damage."
The next day, Carter backed up the earlier American account, telling reporters that U.S. forces had come under attack. "That much I think we can safely say,” Carter said.
Afghan officials claimed that Taliban fighters had been hiding in the hospital, using the building "as a human shield." One senior Afghan commander told NBC News that the bombing had killed at least 15 enemy fighters.
That sparked outrage from Doctors Without Borders, which said there were 105 patients and 80 hospital staff inside. Ten patients, including three children, were killed, along with 12 staff members, a spokeswoman said. "Bombing a fully functioning hospital can never be justified," she said.
The group's general director, Christopher Stokes, said the accounts from the United States and Afghanistan implied that their armed forces had worked together to destroy a hospital. That, he said, contradicted the initial description of the destruction as collateral damage and amounted to "an admission of a war crime."
The U.S. military began backtracking. Army Gen. John Campbell, the coalition's top commander in Afghanistan, admitted that American forces had not been under direct fire. But he said that Afghan forces had asked for air support prior to the bombing.
Campbell also announced that the two countries had ordered investigations of the incident. "If errors were committed, we'll acknowledge them. We'll hold those responsible accountable and we will take steps to ensure mistakes are not repeated."
Campbell wouldn't say whether rules of engagement allowed for Afghans to call in American airstrikes and whether there were proper systems in place to prevent mistakes.
Military officials have told NBC News earlier that Afghans could not call in airstrikes because they did not have the training. But the officials said the Afghans could report to the United States that they were under fire from a location, in which case the United States could call in a strike. The officials added, however, that the United States would have to verify the target first.
Later that day, the White House said that in addition to a Department of Defense investigation, there would also be one conducted by NATO and a third by U.S. military personnel alongside Afghan security officials.
Doctors Without Borders said the United States and Afghanistan could not be relied on for an impartial review because their accounts were constantly shifting. The group called for "an independent, fully transparent investigation."
"It started with a tragic incident, to collateral damage, and now what we hear it was a U.S. strike but on request, under the responsibility of the Afghan government," Nicolai told NBC News. "The reality is they dropped the bombs and they hit a fully functioning hospital at the front line doing a humanitarian duty. So, the responsibility is pushed off, the U.S. military remains responsible for the targets they hit, even if you're part of a coalition."
Campbell appeared before the Senate Armed Services Committee, where he added to the United States' version of events. He testified that U.S. Special Operations Forces "were in close vicinity" to the hospital and were "talking to the aircraft" that launched the bombing.
He also said the airstrike was "a U.S. decision made within the U.S. chain of command," and while Afghan forces asked for U.S. air support, it was up to American forces to conduct a "rigorous review" of the conditions on the ground before launching an attack.
Campbell added: "A hospital was mistakenly struck. We would never intentionally target a protected medical facility."
Campbell declined to offer any additional details of the attack, citing the ongoing investigations.
Doctors Without Borders called for the little-known International Humanitarian Fact Finding Commission to investigate the attack. "This was not just an attack on our hospital, it was an attack on the Geneva conventions," President Joanne Liu said. "This cannot be tolerated."
Later that day, President Obama called Liu to apologize. He did the same in a call to Afghan President Ashraf Ghani, White House spokesman Josh Earnest said.
That did nothing to satisfy Liu.
She released a statement in which she called again for the United States to "consent to an independent investigation led by the International Humanitarian Fact-Finding Commission to establish what happened in Kunduz, how it happened, and why it happened."
Doctors Without Borders said it had sent letters to 76 countries seeking help mobilizing the commission. But the United States and Afghanistan would also have to give their consent.
As of Wednesday, the charity hadn't gotten a response.