The combination of a crisis in Sudan's unity government and fresh violence in Darfur is threatening to trigger a full-blown conflict in the oil-rich region of Kordofan, say observers.
They said that Kordofan, which had increasingly seen the Darfur conflict spill over its borders, could be Sudan's next frontline.
Late last month, suspected Darfur rebel groups killed 10 African Union peacekeepers in Haskanita, which lies on the border with Kordofan. Rebels also launched a deadly raid against police inside Kordofan in August.
Last week, the Sudan People's Liberation Movement suspended its participation in the country's unity government, the most serious snag yet in the peace deal signed by Khartoum and the former southern rebels in January 2005.
Darfur conflict 'spreading'
The Sudanese government accused some rebels of seeking to take the Darfur conflict to Kordofan, while rebel groups alleged Khartoum was building up its military forces in the area.
Sharif Harir, an Asmara-based rebel leader, said: "The conflict is spreading because the Sudanese government is using Kordofan as a base to build up troops."
Harir's Sudan Liberation Army-Unity faction and the Justice and Equality Movement had been blamed for the latest attacks in the area.
Harir said: "If you believe in active self-defence, then you will go after them and not allow them to build up", arguing that Khartoum was seeking to circumvent threatened no-fly zones.
He also added that Kordofan was already rife with discontent towards Khartoum, with an increasing number of groups claiming grievances very similar to those that led to the eruption of the Darfur rebellion in early 2003.
Final settlement talks due
According to one of the key architects of the 2005 north-south peace deal, elements on both sides "are moving the war to Kordofan to dodge attempts to bring peace in Darfur".
Final settlement talks were due to kick off in Tripoli at the end of the month, but a bitter cycle of mutual accusations between Khartoum and the rebels and deep divisions within rebel ranks had cast doubt over the negotiations.
Moreover, the recent spreading of the conflict had left United Nations and African Union mediators scratching their heads as to whether or not the Kordofan issue should be included in the talks.
One of them said: "There is a very strong feeling they will bring the Kordofan issue to the table." But Kordofan's woes were not confined to the proximity with Darfur.
One of the main stumbling blocks in the implementation of the landmark north-south peace deal that ended one of Africa's longest and bloodiest conflicts had been the fate of the Abyei region, which lies in South Kordofan.
A boundary commission to determine the borders of Abyei - which produced a quarter of Sudan's oil in 2005 - yielded a report which Khartoum had rejected, leaving unresolved the issue of whether the region belonged to the north or south.