Mali's President Ibrahim Boubacar Keita has announced that opposition leader Soumaïla Cissé, who was kidnapped by suspected Islamist militants in March, is alive, the AFP news agency reports.

The president is quoted as saying in a speech that the government had proof that Mr Cissé was still alive.

"We know who his captors are. And if it pleases God, he will come back soon," he said.

Mr Cissé, the leader of Union for the Republic and Democracy, was abducted on 25 March while on the campaign trail ahead of parliamentary elections.

The Malian army has been battling militants in the north since 2012.

Mali, along with other countries in the region, has faced an upsurge in Islamist militant violence. The military there is being supported by both a regional force and the French army.