"On the side of the military that includes the SPLA, the police and the prison services, 20 were killed in Fangak town, while 30 of Athor's men were killed," said Philip Aguer.

He was referring to renegade southern general George Athor whose supporters launched a spate of attacks on troops of the south's Sudan People's Liberation Army on Wednesday, shattering a "permanent ceasefire" they signed just last month.

"Sadly, there were 39 civilians killed, including women and children, and 65 others wounded," as well as 30 wounded SPLA troops, Aguer added.

The death toll from the fighting in Fangak town on Wednesday evening and Thursday morning, adds to an earlier toll of at least 16 dead from clashes between southern troops and the rebels in the Door area of Fangak county.