The Secretary-General of the United Nations Ban Ki-moon says that he 'regrets' that neither Salva Kiir nor Riek Machar compromised sufficiently at the most recent round of peace talks in Addis Ababa.

East African mediators adjourned the talks between the two South Sudanese war leaders without achieving a power-sharing agreement but they arranged for the parties to sign a document highlighting "areas of agreement" -- common ground on some issues.

"The Secretary-General takes note of the outcome of the last round of negotiations between President Salva Kiir and former Vice-President Dr. Riek Machar, as reflected in the agreement they signed in Addis-Ababa on 2 February 2015," reads a statement from New York.

"He regrets that neither of them compromised on a mutually acceptable power-sharing formula."

Ban urged South Sudanese leader to "place the interests of the civilian population above their own," calling for a comprehensive and inclusive agreement. 

The next round of talks will take place later this month, again under the auspices of the Inter-Governmental Authority on Development (IGAD).