A man prepares meat at the UN Protection of Civilians site in Malakal, the capital of Upper Nile state, in South Sudan. Picture: Charles Lomodong

Juba -

At least five South Sudanese aid workers were killed on Tuesday by the same militia blamed for the murder of an aid worker in the same area the day before, the United Nations said.

The killings came as militia forces in the north-eastern Upper Nile state battled with deserting soldiers for a third day, with aid workers forced to shelter in UN compounds.

“Two of the victims were murdered in Bunj Town, a third aid worker is reported as missing but presumed dead. Another three died in an ambush as they were attempting to return to the town,” the capital of Maban County, the UN Mission in South Sudan (UNMISS) said in a statement.

It said the local militia responsible - the Mabanese Defence Forces - appears to be targeting civilians of ethnic Nuer origin, apparently in revenge for losses they suffered in clashes with defecting Nuer soldiers.

“Today's heinous crimes come on the heels of the murder of a Norwegian People's Aid (NPA) employee in Bunj yesterday morning by members of the same self-defence militia,” UNMISS added.

The victim was reported to have also been South Sudanese.

It said that ethnically targeted attacks on unarmed aid workers were having a “very drastic” impact on operations to provide food and shelter to more than 127 000 refugees in the area who have fled south from Sudan since South Sudan broke away in 2011.

The recent violence has also displaced thousands of people in the area, prompting the United Nations to warn of the “deteriorating security situation” as refugees pour into a camp at Doro.

The UN mission said Monday it had dispatched a unit of peacekeepers from its base in the Upper Nile State town of Melut to protect its staff in the area, as well as civilians who have taken refuge in UN compounds.

Meanwhile, fractious peace talks to end the country's civil war between supporters of President Salva Kiir and his former deputy Riek Machar resumed in the Ethiopian capital Addis Ababa on Monday. Two previous ceasefires between the two sides quickly broke down.

Fighting erupted on December 15 between troops loyal to the two rivals, who have jousted for control of the new state since its independence from Khartoum in July 2011 after decades of war.

The clashes quickly descended into atrocities along ethnic lines between the country's two principal tribal groups, Dinka and Nuer, to which the two leaders belong. - Sapa-AFP