Nine Turkey-backed Syrian rebels have been killed and 32 were wounded in an operation to push Islamic State militants away from the border area in Syria, in a sign of a fresh surge in clashes.
The rebels have seized control of just over 1000 square km of territory from the Islamic State militant group in the offensive, dubbed "Euphrates Shield", since it was launched on August 24, Turkey's military said.
Turkish warplanes hit 18 targets in the region over the past 24 hours, destroying 15 buildings used by Islamic State fighters, while US-led coalition warplanes killed three of the militants in air strikes, the military said.
Turkey's entry into Syria has raised concerns of a further escalation in an increasingly fraught regional conflict.
Ankara says its efforts to cleanse its border region of Islamic State militants are legitimate under international law as self-defence after months of rocket attacks and bombings in cities along the boundary.
Turkish President Tayyip Erdogan has also made it clear that their forces are in Syria to prevent the Syrian Kurdish YPG militia, which is backed by the United States to fight Islamic State, from expanding areas under its control.