Nineteen Syrian soldiers have been killed in Turkish drone strikes on Idlib.
According to the Syrian Observatory for Human Rights (SOHR), the attacks targeted a military convoy and an army base amid increasing violence.
Turkey also shot down two Syrian fighter jets on Sunday.
Russia, a key backer of the Syrian government, has warned it cannot guarantee the safety of Turkish aircraft in Syrian airspace.
Tensions in Idlib escalated sharply last week when at least 33 Turkish soldiers were killed in an air strike.