Russian and Turkish jets have carried out their first joint strikes on so-called Islamic State (IS) inside Syria, the Russian defence ministry says.
IS was targeted in the suburbs of the town of al-Bab, Aleppo province, where Turkey suffered heavy casualties last month battling the group on the ground.
A Russian spokesman, Lt-Gen Sergei Rudskoi, said the joint action had been “highly effective”.
Russia and Turkey have become leading outside players in Syria’s civil war.
Al-Bab, about 20km (12 miles) from the Turkish border, has been the focus of a five-month Turkish campaign aimed at pushing back both IS and Kurdish forces.
US aircraft carried out strikes on the area earlier this week, also in co-operation with Turkey, but a joint combat operation between a Nato state like Turkey and Russia marks a highly unusual development.