South Sudan army soldiers are pictured in Bor
South Sudan army soldiers are pictured in Bor, 180 km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)
South Sudan army soldiers hold their weapons as they ride on a truck in Bor
South Sudan army soldiers hold their weapons as they ride on a truck in Bor, 180 km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY TPX IMAGES OF THE DAY)
South Sudan army soldiers walk to board a military helicopter at Juba international airport
South Sudan army soldiers walk to board a military helicopter at Juba international airport, before heading to Bor, 180km (108 miles) northwest from the capital December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)
South Sudan army soldiers pose for a photo while celebrating their victory in Bor
South Sudan army soldiers pose for a photo while celebrating their victory in Bor, 180 km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)
A South Sudan army soldier holds a cigarette and his weapon in Bor
A South Sudan army soldier holds a cigarette and his weapon in Bor, 180km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY TPX IMAGES OF THE DAY)
South Sudan army soldiers hold their weapons as they celebrate in Bor
South Sudan army soldiers hold their weapons as they celebrate in Bor, 180km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)
Damaged vehicles are pictured near the entrance of the United Nations camp, after a gun fight between rebels and army soldiers in Bor
Damaged vehicles are pictured near the entrance of the United Nations camp, after a gun fight between rebels and army soldiers in Bor, 180 km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST)
A South Sudan army soldier holds his weapon in Bor
A South Sudan army soldier holds his weapon in Bor, 180km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY TPX IMAGES OF THE DAY)
A South Sudan army soldier carries his weapon as he patrols a road near Bor Airport
A South Sudan army soldier carries his weapon as he patrols a road near Bor Airport, 180 km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)
A South Sudan army soldier rests in Bor town
A South Sudan army soldier rests in Bor town, 180km (108 miles) northwest from capital Juba December 25, 2013. South Sudanese troops have retaken the flashpoint town of Bor in Jonglei state, a week after the town fell to rebels loyal to rebel leader Riek Machar. REUTERS/James Akena (SOUTH SUDAN - Tags: POLITICS CIVIL UNREST MILITARY)