Northern forces with tanks occupied the disputed town of Abyei on Saturday night, scattering southern troops that were there as part of a joint security unit, said Southern officials and a UN spokeswoman. Both north and south claim the fertile region, which lies near several important oil fields.
Hollywood actor George Clooney set up a project to monitor the area by satellite, fearing it could be a flash point that could draw the region back into civil war.
The north's seizure of the town follows several days of fighting and bombing and drew immediate condemnation from the U.S. government.
"We didn't declare war," said southern army spokesman Col. Philip Aguer. "The (Sudanese ruling party) National Congress Party and the Sudan Armed Forces declared war on us." (read more)