Meanwhile, at least 28 members of the Syrian regime forces and their allied militias were killed on Wednesday in an ambush by opposition fighters in the Eastern Ghouta region near Damascus, according to the Britain-based SOHR monitoring group.
Fighting between two major opposition groups in parts of northwestern Syria's Idlib province has killed at least 38 people including eleven civilians, according to the Syrian Observatory for Human Rights (SOHR).
The violence broke out last week between Ahrar al Sham and Al Qaeda-linked Hayat Tahrir al Sham with the reported reasons of power struggle and different ideology. The latter is mainly made up of former Al Nusra Front militants.
Hayat Tahrir al Shami is mainly made up of Syria's former al Qaeda affiliate, known as the Al Nusra Front while the Ahrar al Sham has Free Syria Army's fighters in its ranks.
Opposition ambush kills members of regime forces and their allied militias
Meanwhile, at least 28 members of the Syrian regime forces and their allied militias were killed on Wednesday in an ambush by opposition fighters in the Eastern Ghouta region near Damascus, the SOHR said.
The fighters came under attack by the Army of Islam opposition group as they attempted to advance in the town of Al-Rihan, the Britain-based monitor said.
The Eastern Ghouta region is a major oppsition stronghold near the capital, and it has been the frequent target of regime military operations.
Observatory director Rami Abdel Rahman said opposition fighters opened fire on the regime troops as they entered an area where the fighters had planted mines.
He said the ambush was the deadliest incident for regime forces in Eastern Ghouta since February 2016, when 76 troops were killed in Tal Sawane.
Eastern Ghouta is in one of the four proposed "de-escalation zones" designated in an agreement reached by regime allies Iran and Russia and oppoistion backer Turkey in May.
But the deal has yet to be fully implemented over disagreements on the monitoring mechanism for the safe zones.
In recent weeks, regime warplanes have bombed the Ain Terma area that links Eastern Ghouta to the opposition-held parts of the Damascus neighbourhood of Jobar.
More than 400,000 people have been killed in Syria since its conflict broke out in March 2011 with anti-regime protests.