JUBA, Sudan - Southern Sudanese officials appealed for international help Sunday after northern Sudanese troops seized a disputed border town, and the U.N. Security Council demanded the Sudanese government withdraw its troops from there.

Northern tanks rolled into Abyei on Saturday night, scattering southern troops there as part of a joint security unit and threatening to reignite the country's civil war.

It followed an attack on a convoy of northern soldiers Thursday and two days of aerial bombardment of the area by the north.

The northern army accused the south of violating a peace agreement and said the northern occupation of the area, including Abyei town, would continue until an accord could be reached that would guarantee security and stability in the region.

President Omar al-Bashir's northern ruling party said the northern armed forces were "entrusted with protecting Sudan's territory and stability and the security of its citizens in the south and north."

Both north and south claim Abyei, a fertile region near several large oil fields, and its disputed status has long been recognized as a potential trigger for violence.

Actor George Clooney had set up a project to monitor the area by satellite, fearing a confrontation between the two sides could draw Sudan back into the civil war that killed two million of its people.

The U.N. Security Council, members of which are visiting Sudan, called on the government of Sudan to withdraw its troops from the disputed town.

Southern Sudan fought the north for more than two decades before a 2005 peace deal offered the south the chance for independence. It voted overwhelmingly in a January referendum to secede and is due to become the world's newest country in less than two months.

In a statement Sunday, the council blamed both sides for the violence. It said that the southern forces had attacked the convoy of northern soldiers and that the north had escalated the confrontation by occupying Abyei.