Omar Bongo (file photo)

Africa's longest-serving leader, Gabon's President Omar Bongo, has been sworn in for another seven-year term.

Nearly a dozen African heads of state, past and present, attended Thursday's ceremony in the capital, Libreville.

Mr. Bongo won 79 percent of the vote in Gabon's November election. The victory was his third since Gabon began holding multiparty elections in the early 1990s, after decades of one-party rule.

Opposition candidates contested the results, saying the poll was rigged.

Mr. Bongo has led the central African nation for more than 38 years. Among the world's current heads of government, only Cuba's Fidel Castro has served longer, with 46 years in power.

Some information for this report was provided by AP.