FILE - In this Tuesday, Feb. 8, 2011 file photo, South Sudanese President Salva Kiir, centre-right, is greeted by then Vice-President Riek Machar, centre-left, on Kiir's return to Juba, South Sudan, from Khartoum where he attended the formal announcement of southern Sudan's referendum results. South Sudan President Salva Kiir signed a peace deal with rebels Wednesday, Aug. 26, 2015 in a ceremony witnessed by regional leaders in the capital Juba, after 20 months since the start of fighting between loyalist forces and rebels led by his former deputy Riek Machar. (AP Photo/Pete Muller, File)