Sudan’s disputed border region of Abyei will not hold a scheduled referendum on whether to join the north or south because of a disagreement over who can vote, an aide to President Umar al-Bashir said.

“The referendum will not take place,” Nafie Ali Nafie told the Qatar-based Al Jazeera news channel in an interview yesterday.

Nafie made his comments on the same day that U.S. State Department spokesman Philip J. Crowley said it’s “virtually impossible” for the Jan. 9 vote in Abyei to be held on time, according to the State Department’s website.

The Abyei plebiscite is scheduled to be held simultaneously with oil-rich Southern Sudan’s referendum on independence. The two votes are part of a 2005 peace agreement that ended a 21-year civil war between the Muslim north and the oil-producing south, where Christianity and traditional beliefs dominate. About 2 million people died in the conflict and 4 million fled their homes.

The Permanent Court of Arbitration in The Hague last year set Abyei’s borders to the immediate area around settlements of the Ngok Dinka people, who consider themselves southerners, largely excluding Misseriya cattle-herders who back the north.

The referendum would only be held “if all the people of Abyei participate, not just the Ngok Dinka,” Nafie said.

Permanent Residents

The Sudan People’s Liberation Movement, which governs the southern region, and the Ngok Dinka say that only permanent residents should be eligible to vote.

The Misseriya, who graze their cattle in the region a few months each year, say that as seasonal inhabitants of Abyei, they should also have the right to vote. Misseriya leaders say they fear losing traditional grazing rights in the area, especially if Abyei became part of future independent Southern Sudan.

Pagan Amum, the secretary-general of the SPLM, accused al-Bashir’s government in October of holding Abyei “hostage.”

Clashes two years ago in Abyei between the armies of northern and southern Sudan killed 89 people and forced more than 90,000 people to flee their homes, according to the United Nations.

The African Union’s High Level Panel on Sudan, headed by former South African President Thabo Mbeki, presented the two parties with a “secret” set of proposals to overcome the impasse after previous talks failed to reach an agreement on the region.

While Mbeki declined to give details on the proposals after a meeting between the two parties on Dec. 7, he said they were discussing them.

One of the proposals the two sides are discussing is for the region to be divided between Sudan’s northern and southern regions, Nafie told Al Jazeera.