The UN-Arab League envoy for Syria, Lakhdar Brahimi, has had talks in Turkey amid rising tensions between Ankara and Damascus.
Mr Brahimi met Foreign Minister Ahmet Davutoglu to hear Turkey's perspective on the crisis. A BBC correspondent in Turkey says no breakthroughs were expected, and none were reported.
Several days of cross-border firing followed the killing of five Turkish civilians by Syrian shelling last week.
Earlier this week, Turkey intercepted a Syria-bound plane amid reports it had Russian-made defence equipment aboard.
Syria has dismissed the claim as a lie, challenging Turkey to show any evidence.
In Syria itself, there were reports on Saturday that rebel fighters had shot down a Syrian military jet outside Aleppo.
Footage posted online showed the burning wreckage of what appeared to be an aircraft, but the claim has not been independently verified.