COTONOU: Benin's constitutional court approved President Patrice Talon's re-election on Thursday as associates of a key opposition figure said he was taken into custody by police following the weekend presidential vote.

Talon won 86.3 percent in Sunday's election that opposition leaders say they boycotted after a crackdown on the president's rivals left most of them exiled or disqualified from running in the ballot.

Talon, a cotton magnate first elected in 2016, took a tough stance after Sunday's ballot saying he would track down those responsible for violence during opposition protests in the run-up to the election.

"I praise our behaviour in this election and denounce those who play games that are very dangerous," Talon said on Thursday. "Those who were the authors or instigators of this will have to answer for it."

The West African nation's constitutional court said it had cleared the provisional election results giving Talon a victory and any appeals could be made in the next five days before it approved a final tally.

The court ruling came shortly before opposition figure, Joel Aivo, one of those barred from running in Sunday's election, was taken into custody by judicial police, close associates said.

Aivo is expected to be appear in court on Friday, those sources said.

Judicial authorities did not make any immediate statement.

Talon, 62, appears free of major challenges for now, as his major rivals are sidelined in a West African country once praised as a beacon of multi-party democracy.

Another Benin opposition leader who was barred from contesting Sunday's election was detained last month.

Reckya Madougou was arrested on accusations she plotted to undermine the election with terrorist actions, a charge her lawyer dismissed as politically motivated.

In the lead-up to the election, two people were killed by gunfire when troops opened fire in the air with live rounds to clear an opposition protest blockading a major highway in the centre of the country.

Government officials say security forces responded after they came under fire.

Once hailed for its vibrant pluralism, critics say Benin has veered into authoritarian rule under Talon with a steady campaign against his opponents.

Some have fled Benin, while others were disqualified from running after election law reforms, or targeted for investigation by a special court critics say Talon used against his rivals.

Days before Sunday's election, a judge from the special court said he had fled the country denouncing political pressure to make rulings against Talon's rivals, including to arrest Madougou.

Government officials have dismissed those claims as political manipulation and accused exiled opposition leaders of trying to have the election suspended.