The US Special envoy for Sudan Princeton Lyman said the US fears the possibility of widespread famine in South Kordofan and Blue Nile states and is doubling pressure on Khartoum to accept aid, or face a relief operation without their consent.

Lyman said to Reuters 'the US faces great pressure to discuss ways to deliver aid across the border withiout Khartoum's consent if it continues to refuse to open access for international humanitarian organizations.'

He referred to expert reports stating the growing crisis has already displaced thousands of people from their homes, and could increase to more than a quarter of a million people nearing famine by March this year.

Bill Burns, the US Deputy Secretary of State will visit South Sudan next week on a tour of Africa before heading to Ethiopia to attend the African Union (AU) summit on 29-30 January, and is expected to exert pressure for a stronger regional reaction to the food crisis in Sudan.

He stressed 'if the AU does not solve the problem by the end of January, Sudan will be in a dangerous position.'