President Vladimir Putin has sent condolences after a Russian air strike accidentally killed three Turkish soldiers in northern Syria.
The strike hit a building near the town of al-Bab, believing it to contain Islamic State (IS) fighters rather than Turkish troops, Turkey’s military said.
Eleven others were wounded in the so-called friendly fire incident.
They were supporting Syrian rebels who are locked in a fierce battle to try to capture al-Bab from IS fighters.
Russia and Turkey, who back opposing sides in the Syrian war, have been jointly conducting air strikes on IS in the town in recent weeks