South Sudanese government forces are about to enter Bentiu, the capital city of the oil-rich Unity State, army spokesman Colonel Philip Aguer told Anadolu Agency.
The spokesman said that government forces were also advancing on Bor, the capital city of Jonglei state, which was held by forces loyal to sacked vice president Riek Machar.
Clashes were reported between rebels and government forces were reported in Bor on Thursday.
South Sudan has been shaken by violence since mid-December, when President Salva Kiir accused Machar of standing behind a failed coup attempt.
A subsequent government crackdown landed many of Machar's supporters in jail, but the former VP managed to flee to Jonglei State, a stronghold of his Nuer tribe.
Although Machar had initially denied involvement in the alleged coup, his forces have reportedly captured parts of both the Jonglei and Unity states.
On Wednesday, the United Nations expressed deep concern over what it described as mounting evidence of grave human rights violations and the extra-judicial killing of civilians and captured soldiers in strife-tornSouth Sudan.
The Inter-governmental Authority on Development (IGAD) is now spearheading a mediation effort between South Sudan's warring rivals in Addis Ababa.
By Atem Simon
englishnews@aa.com.tr
