Turkey on Friday shelled fighting positions of the Syrian regime, a day after a soldier had been martyred from fire coming from territory controlled by Syrian government forces.
On Thursday Turkey's Defense Ministry said Russia's Ankara attache was summoned to military headquarters in connection with the attack and was told that the attacks will be "punished in the strongest way".
Similar attacks were carried out on Turkish observation posts in the region earlier this month. After the previous attack, the Turkish military retaliated with heavy weapons.
Russia, which supports Syrian President Bashar al-Assad in his country's civil war, and Turkey, long a backer of the opposition, co-sponsored a de-escalation agreement for the area that has been in place since last year.
The accord has faltered in recent months, forcing hundreds of thousands of civilians to flee. Idlib is the last remaining bastion for opposition fighters after eight years of civil war.
