ANKARA, Turkey (AP) — Turkey has raised the death toll from a Syrian government airstrike on its forces in northwestern Syria the day before to 33 Turkish troops killed.

The fatalities on Thursday marked the largest death toll for Turkey in a single day since it first intervened in Syria in 2016.

The deaths were a serious escalation in the direct conflict between Turkish and Russia-backed Syrian forces that has been waged since early February. The earlier reported death toll was 29 troops. Dozens were also wounded and were being treated in Turkish hospitals.

Rhami Dogan, the governor of Turkey's Hatay province bordering Syria's Idlib region, said 32 injured were being treated in hospitals. Turkey has had 54 soldiers killed in Syria's northwestern Idlib province since the beginning of February.