Abyei,disputed region, c.4,000 sq mi (10,400 sq km), on the border of Sudan and South Sudan. Claimed by both Sudan and South Sudan, the area was given special administative status under the 2004 peace agreement that led to southern independence; Sudan has de facto control of Abyei. The inhabitants of the area include a Dinka group with ties to South Sudanese ethnic groups, and the nomadic Misseriya, an Arab group with ties to Sudan, who graze cattle there part of the year. Abyei also is a significant oil-producing area.
A referendum on whether Abyei would join Sudan or South Sudan was scheduled for Jan., 2011, but never took place. Skirmishes between the southern Sudan People's Liberation Army and the Sudanese army followed, and the area was seized by Sudan shortly before South Sudan declared independence in July, 2011. A UN peacekeeping force was sent to the area as violence broke out and more than 100,000 people were displaced. Sudan withdrew some of its forces in May, 2012. Internationally mediated negotiations toward a resolution of Abyei's status have continued, but little progress has been made.