Russian and Syrian airstrikes targeted the area between the towns of Bara and Bilion in Idlib countryside, killing 34 Turkish soldiers amid reports on more casualties, said the Syrian Observatory for Human Rights.

This comes as tension heightened on Thursday as Russia accused Turkey of providing the rebels in Idlib with mobile anti-aircraft launchers that targeted Russian warplanes without downing any.

The UK-based watchdog group said the Syrian Army continued to advance in the northwestern countryside of Hama province in central Syria and the southern countryside of Idlib, becoming 17 km from the strategic city of Jisr al-Shughour.

Battles also continued to rage around the city of Saraqeb in the eastern Idlib countryside, said the Observatory. It added that the Turkey-backed rebels captured Saraqeb and cut off the M5 highway linking Damascus with Aleppo.

Securing the highway was the aim of a two-month-long Syrian operation in Idlib.

Earlier this week, the Syrian Army announced securing the highway.

Local reports said the Russian-backed army is launching a counter-offensive to re-open the M5.