North-South Sudanese talks on the status of the disputed Abyei region remain deadlocked more than a week after leaders announced they were close to an agreement.

Talks will continue Monday in Addis Abba as northern and southern Sudan attempt to settle outstanding issues ahead of Sudan's scheduled July 9 split. But as the negotiations falter, fears of a return to civil war are mounting.

A week ago Sudanese President Omar Hassan al-Bashir and southern leader Salva Kiir agreed in principle to demilitarize the oil-rich Abyei region and allow an Ethiopian peacekeeping force into the territory. The deal was meant to be signed at a ceremony Saturday evening.

But the signing was delayed and talks remained stalled on Sunday, as negotiators argued over how the region will be policed following the south's independence. Both sides are said to be hardening their positions, and mediators were reported to be increasingly frustrated as their attempts to broker a compromise failed.

A 72-hour cease-fire designed to allow for the delivery of critically-needed supplies to civilians in Southern Kordofan state is also threatened by the diplomatic standoff.

Meanwhile, satellite images of the region show that northern Sudanese forces control the border town of Kadugli and that thousands of civilians have fled to temporary shelters near the United Nations peacekeeping base.

The images, taken Friday by the Satellite Sentinel Project, show at least 89 military vehicles — including heavy ammunition transport trucks — that appear capable and ready to move the battle further south.

The north occupied Abyei last month — one of several developments that have raised fears of renewed war in Sudan as the south becomes independent.

South Sudan voted to split from the north in a January referendum. The sides previously fought a 21-year civil war that ended in 2005.