South Sudan's peace process suffered another setback after fierce clashes in Upper Nile state over the weekend between fighters loyal to a renegade army general and government forces, the two sides said Monday.
Army spokesman Philip Aguer said Johnson Olony -- a former rebel leader who was granted amnesty by President Salva Kiir in April 2013 and integrated into the army as a major general the same year -- had joined the armed opposition movement led by Riek Machar and fought government forces for control of Malakal, the capital of Upper Nile state.
A spokesman for Olony, Brigadier General Nyagwal Ajak Deng, said his forces were retaliating after repeated attacks by the Sudan People's Liberation Army (SPLA) and a militia group loyal to Mr. Kiir.
Several media reports said forces loyal to Olony had seized control of Malakal, but Aguer insisted that the two sides were still fighting for control of the town.
The fighting in the key oil town is the latest in a series of flare-ups of violence in South Sudan's oil-producing states of Unity and Upper Nile since the end of April.
A spokeswoman for the U.N. Mission in South Sudan (UNMISS), Ariane Quentier, said the clashes in Malakal sent hundreds fleeing to the UNMISS protection of civilians site in the town. Many other residents fled Malakal altogether, Quentier said.
The U.N. camp in Malakal now hosts around 29,000 people who have been displaced by nearly 18 months of fighting in South Sudan. In total, nearly 120,000 internally displaced persons (IDPs) are sheltering in seven U.N. camps around the country.
General Deng said Olony's forces shot down two government-piloted helicopter gunships that were attacking camps for people who had fled the fighting in Malakal. Deng said the helicopters were Ugandan, but a spokesman for the Ugandan military has denied any involvement in the alleged aerial attacks.
There are no reliable figures for how many people have been killed since the fighting began in December 2013, but the International Crisis Group estimates that at least 50,000 people have died. In addition, some two million have fled their homes since the country plunged into conflict.
Despite international mediation efforts the warring parties have not been able to reach a peace deal, missing an early March deadline set by IGAD, the regional bloc leading the talks. A cessation of hostilities deal agreed to in January last year was violated almost as soon as it was signed.
John Tanza reported from Washington, D.C.