Bongo's family have ruled for 56 yearsJunta names General Brice Oligui Nguema as leaderFrom house arrest, Bongo appeals for supportFrance, with troops in Gabon, condemns coupMilitary officers in oil-producing Gabon said they had seized power on Wednesday, placing President Ali Bongo under house arrest and naming a new leader after the Central African state's election body announced Bongo had won a third term.Saying they represented the armed forces, the officers declared on television that the election results were cancelled, borders closed and state institutions dissolved, after a tense vote that was set to extend the Bongo family's more than half century in power.Within hours, generals met to discuss who would lead the transition and agreed by unanimous vote to appoint General Brice Oligui Nguema, former head of the presidential guard, according to another televised address.Meanwhile, from detention in his residence, Bongo appealed in a video statement to foreign allies, imploring them to speak out on his and his family's behalf. He said he did not know what was happening.Bongo's plight was a dramatic reversal from the early hours of Wednesday when the electoral commission declared him the winner of Saturday's disputed vote.Hundreds of people celebrated the military's intervention in the streets of the Gabonese capital Libreville, while the United Nations, African Union and France, Gabon's former colonial ruler which has troops stationed there, condemned the coup.The military takeover in Gabon is the eighth in West and Central Africa since 2020, and the second - after Niger - in as many months. Military officers have also seized power in Mali, Guinea, Burkina Faso and Chad, erasing democratic gains since the 1990s and raising fear among foreign powers that have strategic interests in the region."I am marching today because I am joyful. After almost 60 years, the Bongos are out of power," said Jules Lebigui, a jobless 27-year-old who joined crowds in Libreville.Bongo took over in 2009 on the death of his father Omar, who had ruled since 1967. Opponents say the family has done little to share the state's oil and mining wealth with its 2.3 million people.Violent unrest broke out after Bongo's contested 2016 election victory, and there was a foiled coup attempt in 2019.The Gabon officers, calling themselves The Committee of Transition and the Restoration of Institutions, said the country faced "a severe institutional, political, economic, and social crisis", and that the Aug. 26 vote was not credible.They also said they had arrested the president's son, Noureddin Bongo Valentin, and others for corruption and treason.There was no immediate comment from Gabon's government.Bongo, 64, was last seen in public casting his vote on Saturday. Before the vote, he had looked healthier than his more frail television appearances after his 2018 stroke.Unlike Niger and other Sahel countries, Gabon, which lies further south on the Atlantic coast, has not had to battle destabilising Islamist insurgencies. But the coup is a further sign of democratic backsliding in the volatile region.A "contagion of autocracy" is spreading across Africa, said Nigerian President Bola Tinubu, the current chair of West African bloc ECOWAS. He said he was working closely with other African leaders on how to respond in Gabon.UN Secretary-General Antonio Guterres and the African Union condemned the events and called on the military to ensure the safety of Bongo and his family, while China and Russia said they hoped for a swift return to stability. The United States said the situation was deeply concerning."We condemn the military coup and recall our commitment to free and transparent elections," French government spokesman Olivier Veran said.The coup creates more uncertainty for France's presence in the region. France has about 350 troops in Gabon. Its forces have been kicked out of Mali and Burkina Faso after coups there in the last two years.French miner Eramet, which has large manganese operations in Gabon, said it had halted operations.Gabon produces about 200,000 barrels of oil a day, mainly from depleting fields. International companies include France's TotalEnergies and Anglo-French producer Perenco.Concerns about the weekend election's transparency were raised by a lack of international observers, the suspension of some foreign broadcasts and a decision to cut internet service and impose a night-time curfew after the vote. Bongo's team rejected allegations of fraud.On Wednesday, the internet appeared to be working for the first time since the vote. The junta confirmed web access had been restored as well as all international broadcasts, but it said it would keep the curfew in place until further notice.Shortly before the coup announcement, the election authority declared Bongo the election winner with 64.27% of the vote and said his main challenger, Albert Ondo Ossa, had secured 30.77%.Gabon's dollar-denominated bonds fell as much as 14 cents on Wednesday before recovering to trade down 9.5 cents on the dollar.