A Turkish fighter jet on Tuesday (March 3rd) downed a Syrian regime warplane in the north-western province of Idlib and the pilot was killed, the Syrian Observatory for Human Rights said.
It was the third such downing in three days, amid escalating fighting between Turkish forces and Syria's Russian- and Iranian-backed regime.
Meanwhile, a missile fired by regime forces killed nine civilians in Idlib city.
Regime forces have been battling since December to retake the Idlib region, where Turkey backs some opposition groups.
The deadly offensive has caused almost a million people to flee their homes and shelters, and triggered a direct Turkish military intervention last week.
A Turkish F-16 downed the regime plane over Idlib province, the Observatory and a source at the Turkish defence ministry said.
The Observatory said it was not clear if the pilot was killed during the downing or afterwards by opposition fighters, and that his body was mutilated.
A military source confirmed to Syrian state media that one of the regime's planes had been downed.
The Turkish ministry said the regime plane was a L-39.
Children among the dead
Also on Tuesday, a surface-to-surface missile fired by regime forces hit an Idlib residential neighbourhood, killing nine civilians including five children, the Observatory said.
That brings the civilian death toll since December to more than 470, the Observatory said.
The Syrian regime also claimed it had downed a Turkish drone near Saraqeb, two days after it said it had hit three other unmanned aerial vehicles (UAVs).
The Turkish operation comes after a Syrian regime airstrike on Thursday killed 34 Turkish soldiers in the region.
The Observatory says Turkish bombardment has killed 119 regime soldiers and 20 allied fighters since.
On Sunday, the Syrian regime closed its air space over north-west Syria and threatened to shoot down any "enemy" aircraft violating it.