JUBA South Sudanese troops clashed with ethnic Nuer "White Army" militia and other rebel factions loyal to former Vice President Riek Machar late on Monday near the flashpoint town of Bor, government officials said.
"Shootings have taken place just outside, to the north of Bor," Sudan People's Liberation Army (SPLA) spokesman Philip Aguer said by phone from Juba, 190 km (120 miles) south of Bor. Earlier Aguer told Reuters there was fighting in the town.
Information Minister Michael Makuei also said SPLA troops clashed with rebels on the edge of the Jonglei state capital. Bor town Mayor Nhial Majak Nhial said there was no fighting in the town center from where he spoke to Reuters by phone.
Government troops in Bor have for days been bracing themselves for an attack by the feared White Army militia, which also was involved in a 1991 massacre of ethnic Dinkas in Bor. A rebel spokesman has denied Machar controls the White Army.
Two weeks of clashes have already killed at least 1,000 people in the world's newest nation and raised fears of an all-out ethnic-based civil war in the oil producing country.
"We anticipate a full-scale attack soon. The SPLA forces in Bor town are on maximum alert," Aguer added. The rebels were pushed out of Bor on December 24 after days of fierce clashes.
(Reporting by Aaron Maasho and Carl Odera in Juba; Writing by Drazen Jorgic; Editing by Alison Williams)