According to an AFP journalist, Azannai was accused of plotting against the state and incitement to rebellion, after being arrested last week at his party's headquarters in Cotonou in the wake of the attempted takeover.

The detention of the prominent opposition figure, who condemned the coup, is the latest in the wake of the foiled takeover, after some 30 people, mostly soldiers, were jailed Tuesday on treason grounds.

Soldiers announced on national television on December 7 they had toppled President Patrice Talon, but loyalist army forces swiftly defeated the coup plotters with the help of the Nigerian air force.

Several people were killed in the attempted uprising, while some of the mutineers, including alleged coup leader Lieutenant-Colonel Pascal Tigri, remain on the run.

After several hours of questioning at Benin's anti-terrorism court, Azannai was escorted away at dawn by police before being taken into custody, an AFP reporter saw.

While Talon has been praised for spurring economic growth, critics accuse the president of creeping authoritarianism in a country once praised for its democracy, while in recent years Benin has been hit by jihadist violence in the north.

Talon is due to hand over the reins of power in April after hitting the two-term limit. str/bam/sbk/gv