Southern Sudan's final leg to independence is still facing roadblocks.
The issue is the oil-rich province of Abyei.
Sudan's president Omar al-Bashir says his government will not recognise the new state if the South claims Abyei.
A Sudanese envoy has gone further, saying any move by the South on Abyei will lead to war.
But already there is conflict. Since January, 1,000 people have died in clashes between northern militias and the South Sudanese army.
Officials from the South maintain their claim on Abyei. The contested issue was left out of January's referendum for independence.
Princeton Lyman, the US special envoy to Sudan, discussed the current situation in the country with Al Jazeera's David Foster.
