An air strike today left nine Medicins Sans Frontiers (Doctors Without Borders) staff dead and dozens more unaccounted for in the embattled Afghan city of Kunduz, the medical charity said, with NATO saying US forces may be behind the attack.
The MSF hospital is seen as a key medical lifeline in the region, which has been running "beyond capacity" in recent days of fighting which saw the Taliban seize control of the provincial capital for several days.
"At 2:10 am local time... the MSF trauma centre in Kunduz was hit several times during sustained bombing and was very badly damaged," it said in a statement.
"Three MSF staff are confirmed dead and more than 30 are unaccounted for. The medical team is working around the clock to do everything possible for the safety of patients and hospital staff."
But, in a subsequent statement, MSF raised the number of dead to nine, and added that the allied forces were well aware of the hospital's location.
It said air strikes on its hospital in the Afghan city of Kunduz continued for more than 30 minutes after US and Afghan authorities were told of its location.
In a statement, MSF has condemned "in the strongest possible terms the horrific bombing of its hospital".
US forces were carrying out air strikes at the time. The NATO alliance has admitted the clinic may have been hit.
At least 37 people were seriously injured, 19 of them MSF staff. At least 100 patients were in the hospital.
Many patients and staff remain unaccounted for, MSF says.
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.
At the time of the bombing, 105 patients and their caretakers and more than 80 MSF international and national staff were present in the hospital, the charity said.
NATO said US forces may be behind the strike.
"US forces conducted an air strike in Kunduz city at 2:15 am (local time) ... against individuals threatening the force," a NATO statement said.
"The strike may have resulted in collateral damage to a nearby medical facility. This incident is under investigation."
The MSF trauma centre in Kunduz is the only medical facility in the region that can deal with major injuries.
Kunduz has seen heavy fighting since Taliban insurgents stormed the provincial capital on Monday -- the first major city to be captured by insurgents since 2001.
Afghan forces, backed by NATO special forces and US air strikes, have been going from house to house in a bid to flush out insurgents in the city.