If the coup is successful, it will mark the third time in five months that a West African nation has suffered a takeover.
The head of Guinea’s special forces said Sunday that he had “seized” the president of the West African country after a morning of heavy gunfire and reports of a coup in the capital, Conakry.
“We have decided, from now on, to dissolve the Constitution,” declared Col. Mamady Doumbouya, the special forces head, appearing later on state television with Guinea’s national flag draped around his shoulders and members of the military surrounding him.
The move comes barely a year after the president, Alpha Condé, won a contentious third term after changing the Constitution, allowing him to stay in power beyond the two-term limit.
If the coup attempt proves successful, Guinea will become the third West African country to experience a violent transfer of power in the past five months.
In April, the president who had ruled Chad for three decades was killed on the battlefield and replaced by his son in what academics called a “covert coup.” In May, Mali’s vice president, Assimi Goïta, arrested the president, prime minister and defense minister in the country’s second coup within nine months.
Guinea is no stranger to coups.
Before Mr. Condé became the country’s first democratically elected leader in 2010, there were two military takeovers, in 1984 and 2008.
After he assumed office, his government turned Guinea into a major exporter of bauxite, which is used to produce aluminum — but it came at a cost to Guineans. Human rights groups say that mining companies have upended the lives and livelihoods of rural communities.
Colonel Doumbouya said he and his men had the president in custody, and on Sunday, the United Nations secretary-general, António Guterres, calling for his release, said he was following the situation closely. “I strongly condemn any takeover of the government by force of the gun,” he said on Twitter.
Colonel Doumbouya said he was acting in response to the people’s will to confront poverty and endemic corruption.
“Guinea is beautiful,” he said near the end of his televised announcement, offering a brutal analogy: “We no longer need to rape her. We need to make love to her, that’s all.”
On social media, videos circulated of Mr. Condé apparently under heavy guard, his clothes in slight disarray.
Other video showed Guineans taking to the streets in celebration and military vehicles moving down Conakry’s streets, accompanied by dozens of motorcycles, their riders raising fists in the air.
Colonel Doumbouya is a former member of the French Foreign Legion, who, according to videos posted online by Guinean news media, received training at Flintlock, the U.S. military’s biggest annual exercise in Africa.