Uganda's Lord's Resistance Army rebels are preparing for talks in southern Sudan with the Ugandan government.
Joseph Kony is wanted for war crimes
An LRA delegation has arrived in Juba, where the southern Sudanese authorities are expected to mediate in talks.
The rebels claim to be guided by the Biblical Ten Commandments and have caused widespread insecurity in northern Uganda and southern Sudan.
Some LRA leaders are wanted by a UN court for war crimes, a fact that is expected to complicate the talks.
South Sudanese Vice-President Riek Machar - himself a rebel leaders before the formation of the regional government last year - confirmed early preparations were taking place for the LRA talks.
Asked what the purpose of the talks would be, Riek Machar replied "peace talks".
The elusive LRA leader Joseph Kony released a DVD recording in May in which he appeared to call for an end to the 20-year conflict.
The DVD appeared shortly after Ugandan President Yoweri Museveni said he would guarantee Mr Kony's safety if peace talks were agreed by the end of July.
But any talks with the Lord's Resistance Army will be a complex affair, BBC correspondent Mark Doyle reports from Juba.
Some of the LRA leaders, including Mr Kony, have been indicted for war crimes by the International Criminal Court at The Hague, and the UN Security Council has called on the Sudanese to arrest these men.
A delegation from the UN Security Council is currently visiting southern Sudan and is following developments carefully.
The recently created government of southern Sudan is made up of former rebels who used to fight the authorities in Khartoum.
Over the decades of war the LRA became involved in the north-south fighting.
Khartoum backed the LRA to counter Ugandan backing for the southern Sudanese rebels.
The LRA has kidnapped many thousands of children over the years. It turns the boys into fighters or porters and uses many of the girls as sex slaves.
Previous attempts to negotiate an end to the war have failed, with both the Ugandan government and the rebels being accused of lacking commitment to peace talks.