An airstrike killed three civilians and injured 12 others during a transfer to Turkey's observation point in Syria's Idlib, the Turkish Defense Ministry said on Monday.
"We strongly condemn this attack that violates existing agreements, cooperation and dialogue with Russia," the ministry said in a statement.
Early on Monday, a troops transfer to Idlib was initiated to ensure the safety of Observation Point No. 9, to keep supply routes open and prevent civilian casualties in the region, the ministry added.
The airstrike at 8:55 a.m. local time (0555GMT) killed three civilians and injured 12 others in the Turkish convoy.
Turkey and Russia agreed last September to turn Idlib into a de-escalation zone where acts of aggression are expressly prohibited.
The Syrian regime and its allies, however, have consistently broken the terms of the cease-fire, launching frequent attacks inside the de-escalation zone.
The de-escalation zone is currently inhabited by about four million civilians, including hundreds of thousands of people displaced by the regime forces from cities and towns throughout the war-weary country in recent years.
Syria has been locked in a vicious civil war since early 2011, when the Bashar al-Assad regime cracked down on pro-democracy protests with unexpected ferocity.
Since then, hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.
