United Nations - Two rebel groups driven out of Darfur by a Sudanese military offensive now operate mostly in Libya and South Sudan but hope to return to fight again, a UN report said on Monday.
Sudan meanwhile is breaking out of international isolation - the Obama administration eased its sanctions on Friday - giving the Khartoum government "more leeway to pursue a Darfur deal on its own terms," said the report by a panel of experts.
The conflict in the vast desert region of Darfur - it is roughly the size of Spain - erupted in 2003 when ethnic minority rebels took up arms against President Omar al-Bashir's Arab-dominated government, accusing it of marginalising the region.
But in a recent military offensive in Darfur's Jebel Marra area, the Justice and Equality Movement (JEM) and the Sudanese Liberation Army led by Minni Minnawi (SLA/MM) were driven out.
"JEM and SLA/MM no longer have a significant presence in Darfur as a result of the government's effective counterinsurgency strategy," said the report.
"JEM now operates mostly in South Sudan, while SLA/MM operates mainly in Libya. These groups are engaged in mercenary activities and, allegedly, in criminal activities in those countries," it added.
This leaves only one other group controlling some territory in Darfur: the Sudanese Liberation Army (SLA/AW) led by Abdul Wahid al-Nour, who has been living in exile in France.
The JEM and SLA/MM have adopted a "waiting strategy," working to rebuild their fighting forces in Libya and South Sudan until there are "new opportunities to re-engage in Darfur with strengthened military capabilities," said the report.
The UN Security Council is due to discuss peace efforts in Darfur on Friday.
Last week, the council met behind closed doors to hear a report from former South African president Thabo Mbeki, who traveled to Khartoum for talks last month as the African Union's peace envoy.
The council wants all rebel groups to join the Darfur peace process.
At least 300 000 people have been killed and 2.5 million displaced in Darfur since the conflict erupted in 2003, the UN says.