A South Sudan army spokesman said Tuesday it was "a matter of time" before government forces regain control of Bentiu and another town in Unity state that have fallen to rebel forces.
"Unity state in general is a fighting area and it’s just a matter of time that the SPLA will re-establish control of Unity state or these areas of Bentiu and Mayom," said Colonel Philip Aguer, a spokesman for the Sudan People's Liberation Army (SPLA).
"Things will change soon,” he said.
Forces opposed to the government of President Salva Kiir last week overran Bentiu, the capital of oil-producing Unity state, and on Monday said they captured the town of Mayom on the border with Warrap state.
The U.N. Mission in South Sudan (UNMISS) on Monday accused the rebels of singling out people who were hiding during the fighting in Bentiu and killing them based on their ethnicity or nationality.
Aguer called what the rebels allegedly did "barbarism" and said the SPLA will do all it can to dislodge the rebels from areas they control.
“The SPLA is mandated by the constitution to stop those acts of barbarism. And it’s just a matter of time that the SPLA will control the area,” Aguer said. He said the SPLA is still in control of Unity state's oil fields.
Rebels seek to shut down government oil production
Rebels say they want to shut down crude production to prevent the government spending the country's largest source of revenue on weapons.
Lul Ruai Koang, an opposition spokesman, said anti-government troops have fanned out and captured several positions in Jonglei state, including the administrative headquarters of Duk county.
Koang also accused government forces of destroying bridges and other infrastructure in Unity state to try to prevent the rebels advancing beyond Mayom and Bentiu.
Aguer dismissed the allegation.
"It’s the rebels that have intentions to blow up bridges. They want to cover up their activities,” he said.
The recent increase in violence in Unity state has resulted in a sharp rise in the number of South Sudanese seeking shelter at U.N. facilities.
Joe Contreras, the acting spokesman for UNMISS, said there were around 12,000 people sheltering at the base in Bentiu last week, compared to around 4,000 at the start of the month when South Sudan peace talks were put on hold.
The talks are due to resume on Monday after a four-week break. The international community has warned that South Sudan is on the verge of famine if the fighting is not stopped immediately and aid allowed to get through to people in need.