A southern official says a rebel force backed by Khartoum launched attacks on a frontier town near South Sudan's disputed border with Sudan.

South Sudan military spokesman Col. Philip Aguer said Saturday that Friday's attack happened near Malakal, the capital of South Sudan's Upper Nile state.

He says southern troops repulsed the rebels, captured three of them, and impounded a truck belonging to the Sudanese army. He did not say how many people were killed.

The attack is the latest in a series of clashes along Sudan's border with South Sudan, with each side saying it is the victim of the other's aggression.

The south gained independence from the north last year but has unresolved issues relating to oil wealth.