At least 56 rebels and four government soldiers were killed over the weekend as heavy clashes erupted in northeastern South Sudan, an army spokesman said Monday.
Sudan People's Liberation Army (SPLA) spokesman Brigadier General Lul Ruai Koang accused forces aligned with former vice president Riek Machar of attacking government troops near the second largest city of Malakal.
"The rebels of Riek Machar attacked us in two places of our defence, that is Wajwok and Lelo, and we heavily impacted on them. The dead bodies of the rebels confirmed after count was 56," he said, adding that the clashes began Friday evening and ended on Saturday.
Koang said the number of dead could rise to eighty.
"On our side we lost four SPLA fighters and twenty were wounded."
Forces loyal to President Salva Kiir invited journalists to the region on Sunday to show they were in control of the area, and an AFP photographer reported seeing up to 40 bodies in the places he could access.
South Sudan, which gained independence in July 2011, descended into war just two and a half years later when Kiir in December 2013 accused his former deputy and political rival Machar of plotting a coup.
Numerous attempts to shore up a fragile truce failed, and in a major setback to peace efforts, fierce clashes erupted in Juba on July 8 this year between Kiir's forces and those loyal to Machar.
The international community has expressed deep concern over a spread in violence since the July clashes, which pushed the number of refugees from the war-scarred nation past the one-million mark, according to the UNHCR.
In a further blow to peace hopes, Machar last month urged "a popular armed resistance" against his rival's government.
Machar, who fled to Khartoum after the July fighting, last week left for South Africa for medical tests.
An influential group of South Sudanese politicians known as the 'former detainees' after their arrest when war broke out in 2013, warned last week that "the country is on the edge of a precipice".
They said they were "greatly disturbed by the recent increase of war and violent conflict all over agin; its ever deepening intensity and level of brutality; an apparently all-pervasive and creeping sense of resentment and hate".