Former Vice President Riek Machar, who fled Juba two weeks ago following what the Government said was an attempted coup, has formed a delegation to take part in talks in Addis Ababa with the Government of South Sudan.
The four-man committee was announced during a news conference in the Kenyan capital, Nairobi.
The deadline set by IGAD countries for the warring parties to engage in talks expires on Tuesday.
More than 1,000 people are believed to have been killed.