Seven Turkish soldiers have been reportedly killed in the operation against Kurdish fighters in northwest Syria, the highest daily toll for Turkey since it launched the offensive last month.
Five of the soldiers were killed in an attack on a Turkish tank while two others were killed earlier the same day in separate clashes, the Kurdish news portal Rudaw reported, citing the Turkish military.
Turkish Prime Minister Binali Yildirim vowed to make the militias "pay for this twice as much".
Turkey has now reported the death of 14 of its soldiers since launching its offensive against the Kurd-held enclave of Afrin in northern Syria on January 20.
Afrin is held by the People's Protect Units (YPG), a Kurdish militia that Ankara regards as a terrorist organisation. The YPG is allied with the US in other parts of Syria where it is battling the Islamic State terrorist group.
Meanwhile at least 15 civilians were killed in Syria's rebel stronghold of Idlib by government and Russian strikes in retaliation for the downing of a Russian fighter jet there, a monitoring group reported.
The dead included eight people killed overnight by missiles fired from Russian warships in the Mediterranean Sea on the town of Khan al-Subul, in the north-western province of Idlib, the Syrian Observatory for Human Rights added.
Seven others were killed in strikes by government helicopters in Idlib's town of Maasran, the London-based watchdog said.
