Voters in Gabon are electing a successor to President Omar Bongo who died in June after leading his country for 41 years.The late leader’s son is tipped to take power in the oil-rich central African nation. Ali Ben Bongo, a former defence minister in his father’s government, looked set for an easy victory until the fractured opposition formed a united front to challenge him. Three thousand polling booths around the country have been placed under guard. Allegations of vote-rigging have led some analysts to forecast clashes between rival camps. Ali Ben Bongo has issued a stern warning that disorder will not be tolerated. Voters have been told to return to their homes after casting their ballots. Bongo’s rivals, including government minister Andre Mba Obame, have denounced what they say is endemic corruption and favouritism. At least five out of 23 opposition candidates have pulled out of the contest and pledged to back Obame.