Addis Ababa (AFP) - South Sudan's warring leaders failed to reach a deal to end more than a year of civil war, mediators said Friday, with the latest collapse in peace talks paving the way for possible sanctions.Ethiopia's prime minister said South Sudan's President Salva Kiir and rebel leader Riek Machar missed a deadline to reach a peace agreement by midnight Thursday, and that further talks on Friday "did not produce the necessary breakthrough.""This is unacceptable, both morally and politically," Hailemariam Desalegn said in the statement issued by the east African regional bloc IGAD, which has been trying to mediate a peace deal.Hailemariam also gave IGAD's harshest criticism yet of Kiir and his former deputy Machar, whose personal feud has exploded into ethnic massacres, gang rapes and the forced displacement of civilians, pushing the country to the brink of famine."Continuing a war flagrantly disregards the interests of you, the people," he said, addressing the people of South Sudan, whose country only gained independence from Khartoum in 2011 after a long, bitter war."It is an abdication of the most sacred duty leaders have to you, their people: to deliver peace, prosperity and stability," the Ethiopian premier said of Kiir and Machar, both of whom have been implicated in atrocities."I asked them to be courageous in offering compromises and alternatives, rather than only reiterating old positions....