The African Union on Wednesday brought together for the first time for peace talks Sudan and insurgents fighting government troops in two states bordering South Sudan, in a conflict that has affected almost a million people.
Fighting broke out between the Sudanese army and the Sudan People's Liberation Movement-North, or SPLM-North, in the states of South Kordofan and Blue Nile around the time of South Sudan's secession from Khartoum in 2011.
The violence has displaced or severely affected more than 900,000 people, according to the United Nations.
Sudan previously refused to meet the SPLM-North, and accused South Sudan of backing the rebels, charges denied by Juba.
Khartoum altered its position after ties with South Sudan greatly improved last month with the signing of a deal to resume cross-border oil flows, the lifeline for both. Both sides also agreed to open 10 border crossings on Tuesday.
On Wednesday, an AU panel led by mediator Thabo Mbeki, a former South African president, met with Sudanese delegation chief Ibrahim Ghandour and the SPLM-North's leader, Yassir Arman, in Addis Ababa at the start of peace talks, diplomats attending the negotiations said.
Ghandour and Arman were later set to meet directly for the first time, diplomats said.
No quick breakthrough is expected as both sides harbour deep mistrust and even hostility. Diplomats see the fact that talks actually take place as success and hope both will agree to allow the United Nations to deliver badly needed aid via Sudan to rebel-held territories in both states.
In an opening statement to the AU panel and Sudan's delegation, the SPLM-North said it was "looking forward to fruitful negotiations" to address the humanitarian crisis and find a solution for the conflict in both states.
Rebels in South Kordofan and Blue Nile states sided with South Sudan during the civil war with Khartoum, which ended with a peace deal in 2005. They were left on the Sudanese side of the border after southern secession and complain of marginalisation.
"We see clearly that this negotiation represents a new historical opportunity to realise a just peace and peaceful democratic change that will lead to building a strong new Sudanese state on the basis of equal citizenship," SPLM-North leaders said in the statement sent to the media.
The rebels also demanded the release of 600 people they said were held by Sudanese authorities as political prisoners.
The SPLM is part of a an alliance with three rebel groups in the western Sudanese region of Darfur, scene of a separate insurgency, which seeks to topple President Omar Hassan al-Bashir.