Medical charity Doctors Without Borders (MSF) has shut down operations in the Afghan city of Kunduz after an apparent US bombing raid on its hospital, and demanded an independent investigation into what it labelled a war crime.
MSF said 22 people were killed, some of whom burned to death in their beds as the bombardment continued for more than an hour early on Saturday (local time), even after US and Afghan authorities were informed the hospital had been hit.
"Under the clear presumption that a war crime has been committed, MSF demands that a full and transparent investigation into the event be conducted by an independent international body," MSF general director Christopher Stokes said.
Stokes also hit out at claims by Afghan officials that insurgents were using the hospital building as a position to target Afghan forces and civilians.
"These statements imply that Afghan and US forces working together decided to raze to the ground a fully functioning hospital with more than 180 staff and patients inside because they claim that members of the Taliban were present," he said.
"This amounts to an admission of a war crime. This utterly contradicts the initial attempts of the US government to minimise the attack as 'collateral damage.'"
MSF has denied any combatants were present in the facility.
The group said Afghan and coalition troops were fully aware of the exact location of the hospital, having been given GPS co-ordinates of a facility which had been providing care for four years.
It added that despite frantic calls to military officials in Kabul and Washington, the main building housing the intensive care unit and emergency rooms was "repeatedly, very precisely" hit almost every 15 minutes for more than an hour.
It is the only medical facility in the whole northeastern region of Afghanistan that can deal with major war injuries. Its closure, even temporarily, could have a devastating impact on local civilians.
MSF said some 105 patients and their caregivers, as well as more than 80 international and local MSF staff, were in the hospital at the time of the bombing.
The dead included 12 MSF staff and 10 patients, among them three children.
US President Barack Obama offered his "deepest condolences" for what he called a "tragic incident".
"The Department of Defense has launched a full investigation, and we will await the results of that inquiry before making a definitive judgment as to the circumstances of this tragedy," Obama said.