The Turkish military convoy was heading toward an observation post established as part of an agreement between Russia, Iran and Turkey to turn Syria's Idlib into a de-escalation zone.
A Turkish military convoy was attacked en route to one of its observation posts in northwest Syria on Monday, Turkey's Defence Ministry said, adding that three civilians were killed and 12 others wounded in the air strike.
“We strongly condemn this attack that violates existing agreements, cooperation and dialogue with Russia,” the ministry said in a statement.
A troops transfer to Idlib was initiated on Monday to ensure the safety of Observation Point No. 9, to keep supply routes open and prevent civilian casualties in the region, the ministry said. The air strike occurred at 0555GMT (8:55 am local time).
The Syrian Observatory for Human Rights, a UK-based monitoring group that reports on the war, said the convoy was stuck on a highway after air strikes prevented it from continuing southwards. It said a fighter accompanying the convoy was killed.
Violation of de-escalation zones and demilitarised regions
Turkey, Iran and Russia agreed in 2017 to turn Idlib in northwestern Syria into a de-escalation zone where acts of aggression are expressly prohibited. Ankara has a dozen military positions in Idlib.
The Turkish defence ministry said on Monday Russia had been told in advance about the convoy.
"Despite repeated warnings made to the authorities of the Russian Federation, the military operations by the regime forces continue in Idlib region in violation of the existing memorandums and agreements with the Russian Federation, causing great harm to the civilian/innocent people and gradually turning into a humanitarian drama," the statement said.
The northwest is the last major stronghold of the opposition to Bashar al Assad, whose forces have been waging the latest offensive there since the end of April with Russian help.
Turkey, which hosts some 3.6 million registered Syrian refugees and warns it can not accept more, fears the onslaught in Idlib could spark a new influx.
The escalation has killed at least 500 civilians and uprooted hundreds of thousands, many stranded near the border with Turkey, the UN says.
In the past week, the regime has been advancing on Khan Shaykhun, a key town in Idlib, causing most of its population to flee. The clashes between regime forces and opposition and its allied fights have killed close to 100 combatants from both sides.
Syria has been locked in a vicious war since early 2011. Hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.