SOUTH Sudan government troops captured the rebel stronghold of Nasir in Upper Nile state today and took back control of Unity state capital Bentiu yesterday, sending rebels fleeing toward the Ethiopian border. 

The government offensive comes just days after South Sudanese President Salva Kiir told US Secretary of State John Kerry that he was ready to hold peace talks with rebel leader and former vice-president Riek Machar. 

But a spokesman for Mr Machar’s negotiating team in Ethiopia said they first wanted a “programme” that included a timeline for the formation of a transitional government.

The violence is increasingly taking on an ethnic dimension between President Kiir’s Dinka community and Mr Machar’s Nuer community.

Rebel fighters from the Nuer took control of Bentiu in mid-April and slaughtered non-Nuer civilians, leaving “piles and piles” of bodies, UN aid official Toby Lanzer said. 

The UN security council expressed “horror” at the massacre.