A Norwegian aid official says the Sudanese air force dropped seven bombs on the town of Yei in the south of the country, killing three civilians.

The official of the Norwegian People's Aid agency said the attack damaged a community corn flour mill near a hospital.

The agency runs both the hospital and mill.

He said it was the fifth time government planes had bombed Yei since it was captured by the rebel Sudan People's Liberation Army last year.

It is in a strategically important position near the southern capital of Juba - the largest town in the south still under government control.