Military officers said they had seized power in the oil-rich Central African nation of Gabon early on Wednesday, overturning the results of a disputed election that returned the incumbent, President Ali Bongo Ondimba, to a third term in office.
If it succeeds, the coup in Gabon would be the latest in an extraordinary run of military takeovers across a swath of Africa — at least nine in the past three years, including one last month in Niger, where President Mohamed Bazoum was similarly overthrown by the head of his presidential guard.
Mr. Bongo, detained inside his residence, issued a video plea for help. But celebrations erupted in the streets outside, as many Gabonese cheered the apparent demise of a family dynasty that has dominated for a half-century.
By evening, the officers announced Gen. Brice Oligui Nguema, head of the elite Republican Guard that is charged with protecting Mr. Bongo, as Gabon’s new leader. Gabonese media identified him as a cousin of the ousted leader.
A close ally of France, Mr. Bongo won international acclaim in recent years from scientists and conservationists for his stewardship of Gabon’s sweeping forests, which cover nearly 90 percent of the country. A member of OPEC, Gabon is Africa’s seventh largest oil producer.
But Mr. Bongo, 64, also presided over a regime accused of cronyism and corruption in a country where only a minority has shared in its great wealth. Public anger has been simmering for years.
“I don’t know what’s happening,” Mr. Bongo, seated in an ornate armchair, said in a video that was released hours into the coup, and authenticated by an adviser. “I’m calling on you to make noise, to make noise, to make noise — really.”
A louder noise, though, came from his foes.
Footage posted to social media showed jubilant soldiers hoisting General Oligui onto their shoulders and punching the air. The coup leader then drove through the streets of Libreville, cheered by civilian supporters shouting “freedom!”