A rebel group in South Sudan threatened Saturday to attack Warrap state to bring down the local government and called on the United Nations and residents to leave within three days.

The South Sudan Liberation Army, one of several rebel groups in South Sudan, said it would turn its attention to the state after earlier attacking Mayom town in neighbouring oil-producing Unity state, also on the border on Sudan.

Within few days, the people of Warrap will be liberated from abject poverty, corruption and abuse of human rights, it said in a statement.

We would also advise the civilians to evacuate all towns and move to villages in order to be safe, it said.

The United Nations mainly runs humanitarian operations for food deliveries and aid to local people and Southern Sudanese coming from the north.

South Sudan became independent in July after a 2005 peace deal with Khartoum that ended decades of civil war, but the new nation has been struggling to end tribal and rebel violence that has killed around 3,000 people this year.

Rebel and tribal violence undermine stability in South Sudan struggling to build up state institutions. Several rebel militias are fighting government forces in remote parts of the country, which is roughly the size of France.

Officials in South Sudan said earlier Saturday the SSLA had killed 15 people, including nine soldiers, and wounded 18 when attacking Mayom in the morning.

We got attacked in Mayom town today by the militias from 6 to 7 a.m. The militia attacked the town, killed 15 and wounded 18, Unity state Information Minister Gideon Gatpan Thoar said. More than 60 militiamen were killed.

Army spokesman Philip Aguer said: It was indiscriminate, they didn't differentiate between civilians and the army. The killing included a doctor.

Aguer said Mayom was now under army control but the SSLA rejected that, adding in its statement: Within four hours, SSLA forces also managed to capture Tomor town and they are now advancing towards Bentiu town.

(Reporting by Hereward Holland; Writing by Ulf Laessing; Editing by)