Medical aid group Medecins Sans Frontieres (MSF) said on Saturday its hospital in the Afghan city of Kunduz was partially destroyed, three staff were killed and 30 staff were unaccounted for after overnight bombing.

Fighting has raged around the northern provincial capital for the last six days after Taliban militants captured the city in their biggest victory of a nearly 14-year insurgency.

"We are deeply shocked by the attack, the killing of our staff and patients and the heavy toll it has inflicted on healthcare in Kunduz," MSF said in a statement.The group described the incident as an "aerial attack", but it was unclear if the bombing was carried out by Afghan forces or U.S. military.

Taliban fighters in Kunduz were still holding out against Afghan troops on Friday, a day after government forces recaptured most of the city.