Former U.N. Secretary-General Kofi Annan was due in Kenya on Tuesday to mediate a dispute over the country's presidential election, which triggered riots and ethnic fighting that killed more than 600 people, according to a report of the Associated Press. The Dec. 27 election returned President Mwai Kibaki to power for a second five-year term, with official results putting opposition leader Raila Odinga second in the closest presidential race in Kenya's history. Annan was due to arrive late Tuesday to try to bring the two sides together, as U.S. Ambassador Michael Ranneberger urged a political settlement. «The tragedy Kenya is now suffering, and the extremely bitter polarization of Kenyan society, demands that all leaders and institutions speak in a responsible, respectful and dignified tone,» Ranneberger said in a statement.