guardian.co.uk, Sunday 12 June 2011 12.59 BST
With South Sudan on the verge of independence, a new wave of fighting and displacement is spreading across the disputed border areas.
The northern government in Khartoum appears determined to impose its rule across the remainder of the country by force, calculating that the Sudan People's Liberation Army (SPLA) will not want to jeopardise the south's secession by responding militarily. Unless robust action is taken by the UN security council now, we might see further Darfur-style mass displacements and the entire peace process unravelling.
Sudan's peace deal, which expires on 9 July – the date the southern region is officially due to secede – was called the comprehensive peace agreement (CPA) because it was supposed to find a solution to all of the country's interlocking conflicts, not merely to end the war in the south.
As well as granting southern Sudan's people a vote on independence last January, there were special protocols dealing with the three "contested areas" that straddle the new border: Abyei, South Kordofan and Blue Nile.
These are predominantly inhabited by pro-southern African tribes that supported the SPLA during the war. Abyei's inhabitants were granted a referendum on joining the south, while the people of South Kordofan and Blue Nile were offered an ill-defined process of "popular consultation" on their future status. None of these aspects of the CPA have yet been implemented.
Although the southern referendum went more smoothly than most people expected and more than 98% of southerners voted peacefully to secede, the situation has deteriorated across the contested areas, culminating in last month's invasion of Abyei by northern Sudanese armed forces and the displacement of its indigenous population of Ngok Dinkas. The UN estimates that nearly 100,000 people have fled from Abyei.
Last week, the security council demanded the Sudanese army withdraw but Khartoum has failed to comply – and now the conflict appears to be spreading across the disputed border region, with fighting within South Kordofan's capital Kadugli and northern aircraft reported to be bombing the surrounding Nuba mountains as well as SPLA positions south of the border.
John Ashworth of the Sudan Ecumenical Forum says: "Military activities by [the Sudanese army] in South Kordofan are beginning to look increasingly like ethnic cleansing, and are raising fears of a repeat of the genocide which took place in the Nuba mountains in the early 1990s … The military takeover of Abyei was relatively easy, but the Nuba mountains and Blue Nile will be a different matter. Already heavy fighting is taking place in South Kordofan, with [the army] using jet fighter-bombers and Antonovs to bomb villages."
In both states there are indigenous fighters, experienced after many years of guerrilla warfare on their home turf, ready to defend their homes against aggression.
The SPLA still has an estimated 40,000 troops north of the border, natives of South Kordofan and Blue Nile. Following last month's occupation of Abyei, Khartoum gave an ultimatum that these forces had to be transferred to the south before June. When this deadline expired, the northern army began to move against them.
South Kordofan is crucial to Khartoum: not only was it a key battleground in the last civil war and is adjacent to Abyei, Darfur and the undemarcated border with South Sudan, it also contains all the oilfields still remaining in north Sudan.
The UN and NGOs have had to evacuate staff from Kadugli, and thousands of its inhabitants have fled since fighting broke out. About 10,000 are sheltering near the UN compound outside Kadugli.
Trouble began brewing after last month's disputed gubernatorial elections in South Kordofan, won by the ruling National Congress party's Ahmed Mohammed Haroun (indicted by the international criminal court for allegedly masterminding the atrocities in Darfur ). The Sudan People's Liberation Movement (SPLM) refused to accept the result, claiming widespread fraud.
The SPLM candidate, deputy governor Lieutenant General Abdelaziz Adam al-Hilu (who had led the SPLA forces in South Kordofan prior to signing the Swiss-brokered Nuba mountains ceasefire agreement in January 2002), has now fled Kadugli with many of his troops.
The SPLM complains that the Egyptian contingent of UN peacekeepers stationed in South Kordofan failed to act to protect civilians – which, as the UN concedes, also occurred with the Zambian contingent in Abyei. It is calling on the UN security council "to raise their mandate from chapter VI to chapter VII, replace the Egyptian forces, impose a no-fly zone in the region, and force [northern troops and militia] to move out the region immediately".
Suleiman Musa Rahhal of Nuba Survival says: "Haroun is wanted by the ICC for the genocide in Darfur but he was also responsible for many of the atrocities committed in the Nuba mountains in the last war. Now it is happening all over again. The Nuba people were forgotten by the CPA and have been ignored by the international community. Unless there is a robust response from the security council, we could see a repeat of Darfur."