Sudanese officials claim that 400 South Sudan troops were killed during the battle for the flashpoint town of Heglig, an oil-producing area claimed by both countries.

South Sudanese troops completed their withdrawal from Heglig Sunday, saying the number of soldiers killed is just a fraction of what Sudan claims. Estimates of casualties in Sudan are impossible to verify.

The showdown over Heglig and its lucrative oil fields is raising fears of a full-scale war, less than a year after South Sudan declared independence from the north.

South Sudan said it pulled troops out of Heglig because of international pressure. But Sudan says the southern forces withdrew because they were on the verge of defeat.

The international community has pressed both sides to halt cross-border attacks and restart dialogue to settle unresolved issues, including oil revenue and citizenship disputes.

U.S. President Barack Obama is appealing to both governments to avoid war and return to peace talks. He says there is no military solution to their dispute.

Mr. Obama Saturday called on both governments to stop arming rebels across their borders and to allow aid groups access to people caught in the fighting.

The north and south signed a peace deal in 2005 that ended a 21-year civil war that killed more than two million people. The deal included an independence referendum for the south.