The Obama administration says Sudan risks killing a process of normalizing relations with the U.S. if it continues a military campaign in areas disputed with Southern Sudan.
State Department spokesman Mark Toner expressed U.S. concerns Tuesday about the worsening situation in the state of Kordofan. He said Sudan was blocking aid flights from landing while tens of thousands need assistance. Both northern and southern forces are obstructing humanitarian access by land.
Toner also criticized Sudan's aerial campaigns and military buildup near the central city of Kadugli.
He said Sudan won't progress in talks to be removed as a state sponsor of terrorism if it further escalates the situation.
Sudan's south gains independence next month. The two sides are supposed to settle rival claims on border areas peacefully through negotiations.