Abyei is 10.000 square kilometres large and is placed on the border between Sudan -the country that is currently controling the region- and South Sudan. When the two states separated in 2011, Abyei inhabitants, the Ngok Dinka, were promised a plebiscite to decide whether they would like to belong to Sudan or South Sudan. But since then, no vote has been organized: Sudan is blocking the holding of a referendum. Khartum argues it will continue to do so unless an agreement on who is entitled to vote is reached.

At first sight the issue could seem easy and simple, but it is not. The Ngok Dinka are Abyei's permanent dwellers. Both the Sudanese and the South Sudanese governments think that the Ngok Dinka would overwhelmingly vote in favour of joining South Sudan. In this country, the Dinka are the largest ethnic group. If they chose to remain in Sudan, they would be a very tiny minority in an Arab majority state.

But things are more complicated. The lands of Abyei are also used by the nomadic Misseriya Arab pastoralists. Their region of origin is situades north to Abyei, and they only live in Abyei during several months in the rainy season so that their cattle can drink and eat. Sudan considers that Misseriya Arabs should also be allowed to vote in the referendum because, as explained, they also are partially dwellers in Abyei. According to Khartum's calculations, the Misseriya Arabs would vote against joining South Sudan.

The African Union (AU) named former South African President Thabo Mbeki as mediator in the conflict. After some consultations, the Peace and Security Council of the AU suggested that Abyei's future should be decided in a referendum in October 2013, and that only permanent inhabitants (i.e. the Ngok Dinka) could vote. This would most likely lead Abyei to re-unification with South Sudan.

But Khartum insists on the fact that the vote cannot be held until Sudan agrees. The Sudanese Government says that it will block any initiative to implement the AU proposal. Sudan Tribune wrote some days ago that the British Government holds the same opinion as the Sudanese, and that the referendum should only be called when Khartum and Juba reach an agreement.

Oil is a factor

In addition to ethnic issues, oil is another factor in the conflict. Abyei is placed in a wider region where several important oil fields are located. Next to Abyei, an important pipeline pumps oil from South Sudan to the Sudanese port of Port Sudan, on the western shore of the Red Sea. From there, the oil reaches the East Asian markets. Sudan has threatened several times to block the pipeline, a move that would prevent the South Sudanese oil from being sold.

Nevertheless, last week the Sudanese President, Omar al-Bashar, and the South Sudanese President, Salva Kiir Mayardit, annouced that they had reached a deal so that the oil could continue going through the pipeline. Sudanese media say that a new phase in Al-Bashar-Kiir relationship is now open, in a framework of an enhanced dialogue that could pave the way for some sort of agreement on the Abyei referendum. Even though, it is quite doubtful that the data proposed by the AU -next month- could be met.