"There were clashes for the past two days after Athor's men attacked our forces," said Philip Aguer, of the south's Sudan People's Liberation Army (SPLA).

The clashes, which began on Monday in the region of Fangak in northern Jonglei state, are the latest in a series of bloody battles between the militia and army in past weeks.

"Athor is claiming that he has killed over 80 of our soldiers, but this report is not accurate," said Aguer. "The casualties for the SPLA are likely to be half off that, around 40 men killed.