Sudan's President Omar al-Bashir has expressed concern about instability in neighbouring South Sudan and other volatile states in the region, official media reported Sunday.
The United States and other foreign powers stepped up pressure on South Sudan's feuding ethnic factions to settle their differences, as Washington dispatched an envoy to the violence-wracked region.
Sudanese rebels say they have launched a major operation against an area in South Kordofan which a controversial counter-insurgency unit showed off to journalists after "liberating" it last week.