West African leaders on Sunday told Mali's ruling junta to release 46 Ivorian troops taken prisoner in July or face sanctions, officials said.

"We ask the Malian authorities to release the Ivorian soldiers by January 1, 2023 at the latest," Omar Alieu Touray, president of the Economic Community of West African States (ECOWAS) commission, told journalists at a summit in Nigeria.

Gambian diplomat Touray also said the West African bloc reserved the right to act if the soldiers are not released by January 1.

If Mali fails to do so, ECOWAS will impose sanctions, a West African diplomat told AFP.

Togolese President Faure Gnassingbe, who has been mediating between Mali and Ivory Coast on the issue, will travel to Mali to "demand" the release of the soldiers, the diplomat added.

The Ivorian troops were arrested on July 10 on their arrival at the airport in Mali's capital Bamako.

Ivory Coast says the troops were sent to provide backup for the UN peacekeeping mission in Mali, MINUSMA, and are being unfairly detained.

Mali says the troops are mercenaries and has placed them in custody on charges of attempting to harm state security.