Officials have announced South Sudan's warring leaders have agreed to share power once again in the latest effort to end a five-year civil war.

The agreement initialled on Wednesday will be signed on August 5, Sudan's Foreign Minister Al-Dirdiri Mohamed Ahmed said.

President Salva Kiir will lead South Sudan's government during a transitional period and armed opposition leader Riek Machar will return as first vice-president.

A similar arrangement fell apart in July 2016 when fighting erupted in the capital and Mr Machar fled the country on foot.