A Turkish observation post in Syria's Idlib region was attacked with mortar fire and shelling from an area controlled by Syrian government forces, causing damage but no casualties, the Turkish Defence Ministry said on Sunday.
The ministry said its forces immediately retaliated with heavy weapons and it made representations to Moscow over the incident, the second attack of its kind within a week.
"It is impossible for us to tolerate the regime's harassment targeting our soldiers. We will put them in their place," Turkish Foreign Minister Mevlut Cavusoglu said in a televised speech in the southern Turkish province of Hatay, bordering Syria.
The ministry did not specify when the shelling occurred, but said the attack was launched from what it named the Tall Bazan area and it was assessed to be deliberate.
Russia, which supports Syrian President Bashar al-Assad in his country's civil war, and Turkey, long a backer of rebels, co-sponsored a de-escalation agreement for the area that has been in place since last year.
But the deal has faltered in recent months, forcing hundreds of thousands of civilians to flee. Idlib is the last remaining bastion for anti-government rebels after eight years of civil war.
Cavusoglu said the latest "aggression" was contrary to the Idlib agreement which Turkey signed with Russia.
"It is the responsibility of Iran and Russia, with which we have worked in close cooperation on Syria, to halt the regime," he added.
On Thursday Russia and Syria gave sharply conflicting accounts of a previous attack on a different Turkish outpost.
Turkey blamed Syrian government forces for that earlier attack but Moscow said it was carried out by Assad's rebel enemies. Russia said on Wednesday that a full ceasefire had been put in place in the area, but Turkey denied this.