"It has been agreed that there will be four vice presidents: the current two vice presidents, plus Riek Machar (who) will assume the position of first vice president, and then the fourth position will be allocated to a woman from the opposition," Al-Dierdiry Ahmed said, following the meeting in Kampala aimed at ending more than four years of civil war in South Sudan.

The foreign minister said South Sudan's president Salva Kiir and rebel leader Riek Machar had agreed to the proposal, but that further details would be discussed at negotiations to be held in Khartoum and Kenya in the coming days.

The latest agreement is part of renewed regional diplomatic efforts to end a conflict that has killed tens of thousands and forced millions from their homes since December 2013.

The war began when Kiir accused Machar, his former deputy, of planning a coup.

A similar power-sharing deal, that returned Machar to the vice presidency, was signed in 2015 but fell apart a year later in a deadly battle that saw Machar flee into exile.

On 27 June Kiir and Machar signed a ceasefire agreement which was further consolidated on Friday in the Sudanese capital, Khartoum, when the warring parties struck a deal to withdraw troops from urban areas.

Ahmed said the new proposal was "accepted by the government" and that Machar's opposition had accepted the deal "in principle" but would "consider it and come up with the final position" following further negotiations, to begin in Khartoum on Sunday.

Saturday's day-long meeting was hosted by Uganda's President Yoweri Museveni and was attended by Sudanese President Omar al-Bashir as well as representatives of the opposition.