Christian Solidarity Worldwide has called for a referendum to be held on the future of Abyei after the UN confirmed that Sudan had withdrawn troops from the contested border region.

Sudanese forces seized control of Abyei in May last year, just before the South's secession following a protracted civil war.

The 2005 Comprehensive Peace Agreement that ended the civil war stipulated a referendum on the future of the Abyei, which is claimed by both sides.

The incursion of Sudanese troops caused the referendum to be postponed as at least 130,000 Ngok Dinka residents were displaced and access for humanitarian organisations to the area was restricted.

The terms of the referendum are also disputed, as Sudan argues that the Miseriya, a nomadic northern tribe that grazes its livestock in Abyei, should be allowed to vote. South Sudan maintains that only the Ngok Dinka people who reside in Abyei should be allowed to vote.

An Abyei Elder told CSW, “We would like to have a referendum and anyone who has actually been resident in Abyei is welcome to participate. The Ngok Dinka have been peaceful with the Miseriya tribes and will continue to welcome them to graze and take water, but they have their own residences and should not be included in the referendum.”

South Sudan withdrew its troops from the region earlier in the month in line with a demand by the UN Security Council for the area to be demilitarised by 16 May.

CSW welcomed news of the withdrawal of Sudanese troops, and called upon the international community to facilitate the referendum and ensure an end to fighting along the north-south border.

It has also called for immediate humanitarian access to the Nuba Mountains, where it warns that the population faces "imminent" starvation.

CSW’s Advocacy Director Andrew Johnston welcomed the troop withdrawal and the resumption of peace talks in Addis Ababa.

However, he said these steps should not be allowed to obscure the Sudanese government’s "responsibility for the creation of humanitarian crises not only in Abyei, but also in Darfur and most recently, in the Nuba Mountains", where he said the civilian population was being "deliberately targeted" by the military.

Mr Johnston raised further concern over clashes occuring intermittently along the unresolved north-south border.

"The international community is currently investing vast resources into securing peace in the area," he said.

"However, until there is more a comprehensive approach to these problems, a sustainable peace will continue to remain elusive.

"In order to ensure a viable and sustainable peace, from this point onwards the Sudanese government must be held to account for all violations of its international obligations, regardless of where they occur.”