Oct. 3, 2015: Aftermath of airstrike by US forces on MSF clinic in Kunduz, Afghanistan. (Photo: PAN)
The medical charity MSF says at least nine of its staff were killed in the Afghan city of Kunduz after a clinic was hit by an air strike on Saturday.
US forces were carrying out air strikes at the time. The Nato alliance has admitted the clinic may have been hit.
MSF says 37 people were seriously wounded in the attack, 19 of whom are its staff.
There has been intense fighting in Kunduz since Taliban fighters swept into the northern city on Monday.
It was the first major urban centre to fall to the Taliban in 14 years.
Medecins Sans Frontieres (MSF) said its clinic was hit several times during "sustained bombing and was very badly damaged" at 02:10 local time (22:40 GMT) on Saturday.
Many patients and staff remain unaccounted for, it said.
Oct. 3, 2015: These MSF staff appear to be in shock following the attack. (Photo: MSF)
Oct. 3, 2015: MSF says surgery took place in the undamaged parts of the hospital following the attack. (Photo: MSF)
The organisation says that all parties to the conflict, including Kabul and Washington, had been told the precise GPS co-ordinates of the hospital in Kunduz on many occasions.
The bombing continued for more than 30 minutes after US and Afghan officials were informed of the proximity to the hospital, the charity tweeted.
A spokesman for US forces in Afghanistan, Col Brian Tribus, said: "US forces conducted an air strike in Kunduz city at 02:15 (local time)... against individuals threatening the force.
"The strike may have resulted in collateral damage to a nearby medical facility."
The incident is being investigated, he added.
The operating theatre and emergency department were among the parts of the hospital complex hit, according to Adil Akbar, a doctor who spoke to AP.
"I managed to escape after [the] attack but I know that most of the staff and even some of the patients are missing," he said.
Oct. 3, 2015: MSF released this photo of its hospital in Kunduz on fire after the bombings. (Photo: MSF)
The charity says it does not have final figures for the dead and injured. However, it says when the bombardment took place, 105 patients and their caretakers were in the hospital, along with more than 80 MSF staff.
Most of MSF's staff in Kunduz are Afghan, it says.
The BBC's Emal Pasarly, in Kabul, says there has been fighting going on in Kunduz every night, and the area where the hospital is was the centre of the fighting on Friday night into Saturday.
Local people said that helicopters were firing at the hospital, he reports.
Afghanistan's Interior Ministry said that security forces had evacuated 80 people, including 15 foreign aid workers, from the damaged hospital.
Taliban were in or around the hospital overnight, it said.
A Taliban spokesman said none of their fighters were at the hospital at the time of the bombing.
Afghan officials said the government had regained control of Kunduz on Friday, but the Taliban denied the city had been retaken.
Eyewitnesses said they saw Taliban fighters on the streets or hiding in civilian houses.
Taliban leader Mullah Akhtar Mansour had described the seizure of Kunduz as a "symbolic victory".
Kunduz, with a population of around 300,000, is one of Afghanistan's largest cities and strategically important both as a transport hub and a bread-basket for the region.
The US-led Nato combat mission in Afghanistan ended in December 2014, but Nato forces remain for training purposes.
Nato's Resolute Support Mission, which was launched in January 2015, consists of more than 13,000 troops from 42 countries. The US contributes around half of these.