Syrian government forces have killed five Turkish soldiers in an attack in northwestern Syria - the first significant clash between the two sides.
Turkey's military says it has killed more than 100 Syrian government soldiers in Idlib province in retaliation for the deaths of its troops.
Syrian soldiers are trying to recapture the last rebel-held province but Turkey is trying to counter this advance as the attacks are sending more Syrian refugees fleeing towards its borders.
Meanwhile Syria's ally, Russia has met Turkish officials to find a diplomatic solution to this crisis.
Al Jazeera's Hashem Ahelbarra reports from Istanbul, Turkey.