South Sudan President Salva Kiir flew out of Juba Friday for the Ethiopian capital to hold direct talks with rebel chief Riek Machar, the foreign minister said. \"President Salva Kiir is travelling today to Addis Ababa to meet the rebel leader Dr. Riek Machar under the auspices of the Prime Minister of Ethiopia Hailemariam Desalegn,\" Foreign Minister Barnaba Marial Benjamin told reporters, shortly before the airplane took off. Machar arrived Thursday night in Addis Ababa, where the authorities had closed a major highway Friday, ahead of Kiir's arrival. The meeting, aimed at stemming almost five months of bloodshed, comes the day after the United Nations said both sides in the country's brutal civil war have likely carried out crimes against humanity.