MSF said a bomb was dropped on the pharmacy, burning it to the ground and damaging the hospital, followed by another drone bomb on Old Fangak, a town in the Greater Upper Nile region, where at least seven people were killed.

"Old Fangak Hospital is the only hospital in Fangak county, serving a population of over 110 000 people who already had extremely limited access to healthcare," MSF said in a statement.

It was not immediately clear who carried out the attack or what the motive was.

Government and army spokespeople could not immediately be reached for comment.

South Sudan has formally been at peace since a 2018 peace deal ended a five-year civil war between forces loyal to President Salva Kiir and those loyal to First Vice President Riek Machar.

However, the March arrest of Machar on charges of trying to stir up a rebellion has sparked international concern that conflict could flare anew.

--Reuters--