The medical charity MSF says 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”.
MSF says the number of its staff killed has risen to nine, from three.
US forces were carrying out air strikes at the time. The Nato alliance has admitted the clinic may have been hit.