Turkey's president says Russian airstrikes that have targeted some foreign-back insurgents in Syria are unacceptable and warned Moscow that it runs the risk of alienating itself in the region.

Recep Tayyip Erdogan said before departing for France on Sunday that Russia was making a "grave mistake" and that Turkey was "saddened and perturbed" by its actions.

Russia says the airstrikes that began Wednesday are targeting the Islamic State group and al-Qaida's Syrian affiliate, but at least some of the strikes appear to have hit Western-backed rebel factions.

An activist group said Saturday that the Russian air raids have killed 39 civilians.

On Friday, Turkey and its allies issued a joint statement asking Moscow to cease attacks on the Syrian opposition and to focus on fighting IS.