At least 75 people, including 60 rebels, were killed Saturday in the Unity state of South Sudan when the Sudan People's Liberation Army (SPLA) repealed an attack by a rebel militia, an official said.

"An armed militia attacked Mayoum county on Saturday morning and the SPLA forces responded to the attack," Gideon Gatpan Thoar, information minister of the Unity state, told Xinhua.

"Fifteen civilians were killed and 18 others were injured, while around 60 of the rebels were also killed in the battle which lasted for about an hour," he added.

"We are still counting the number of the dead and the wounded, but we are sure that 60 of the rebels were killed. There are also injured people among civilians," the official said.

A rebel militia in Unity on Friday announced that it was determined to launch violent resistance against the state authorities and urged the personnel of the NGOs and UN organizations to leave the area in a week's time for their safety, arguing that the "people of the state" would launch a violent resistance against the government of the state governor, Taban Deng.

The group, calling itself "South Sudan Liberation Army", was formerly loyal to Peter Gadet, an officer who defected from the ruling party of South Sudan, the Sudan People's Liberation Movement (SPLM).

The newly born state of Unity is suffering from increasing tribal violence that has claimed lives of around 3,000 people this year.