NEW YORK, Shawwal 27, 1438, Jul 21, 2017, SPA -- The United States warned leaders in South Sudan on Thursday that they risk losing U.S. support if they don't participate in a high-level forum and stick to deadlines for a cease-fire and political process to end their civil war. U.S. deputy ambassador Michele Sison said the Revitalisation Forum being organised by the regional group IGAD is "the last chance" for salvaging the August 2015 peace agreement, according to the Associated Press. "The United States expects that it will lead to a realistic and meaningful outcome," Sison said. "If South Sudan's leaders do not participate in this high-level forum in good faith and stick to its deadlines, the United States will need to review our position and priorities on support for the peace agreement and its implementing bodies." For the United States, Sison said, "the bottom line is that we want this regional mediation to succeed, and we need to see South Sudan's leaders engaged in it, at long last." There were high hopes that South Sudan would have peace and stability after its independence from neighboring Sudan in 2011. But the country plunged into ethnic violence in December 2013 when forces loyal to President Salva Kiir, a Dinka, started battling those loyal to Riek Machar, his former vice president who is a Nuer. --SPA 02:08 LOCAL TIME 23:08 GMT www.spa.gov.sa/w450926