South Sudanese government troops on Friday recaptured the key northern oil city of Bentiu from rebel forces, a spokesman said.
"Bentiu now is under our control," said presidential spokesman Ateny Wek Ateny.
Bentiu is the capital of the oil-rich Unity State, and was one of two cities under rebel control.
There was no immediate comment from the rebels.
However, the independent Tamazuj radio station said the city fell back into government hands around midday after rebel fighters abandoned their positions in the face of a huge offensive by government troops.
Quoting witnesses, the radio also said there was fighting within the ranks of the rebel force prior to the fall of the city, while several rebel fighters left in the city were shot dead by government forces while trying to seek shelter at a UN compound.