African Union mediators have arrived in South Sudan's capital Juba for talks aimed at averting a new civil war after First Vice President Riek Machar was placed under house arrest last week.
President Salva Kiir's government has accused Machar, a longtime rival who led rebel forces during a 2013-18 war that killed hundreds of thousands, of trying to stir up a new rebellion.
Machar's detention last Wednesday followed weeks of fighting in the northern Upper Nile state between the military and the White Army militia. Machar's forces were allied with the White Army during the civil war but deny any current links.
The UN warns of a potential return to civil war, urging leaders to prioritise peace.
The AU delegation's flight arrived at Juba's airport on Wednesday afternoon with a "Council of the Wise" which included former Burundian President Domitien Ndayizeye and former Kenyan judge Effie Owuor.
Machar's SPLM-IO party said in a statement that it "warmly welcomes the arrival of the Council of Wise as part of ongoing efforts to de-escalate tensions and support the peace process".
The AU's Peace and Security Council called in a statement on Tuesday for Machar's "immediate and unconditional release", saying recent developments threaten the 2018 peace deal that ended the war.
Kenya's former Prime Minister Raila Odinga came to Juba on Monday on behalf of an East African regional body to mediate between the rival camps. Odinga met with Kiir but said he was not allowed to see Machar.
Analysts say Kiir, 73, appears to be attempting to shore up his position amid discontent within his own political camp and that the war in neighbouring Sudan has worsened security conditions by leading to an influx of weapons.
The 2013-18 war was contested largely along ethnic lines, with fighters from the Dinka, the country's largest group, lining up behind Kiir, and those from the Nuer, the second-largest group, supporting Machar.
