At least 30 Syrian rebels and 12 members of the Islamic State (IS) terrorist group died during clashes on Wednesday morning in western Syria, the Syrian Observatory for Human Rights (SOHR) said.
The IS extremists managed to regain control of large areas and cut the supply routes of the rival insurgent factions, including some Islamist groups, Efe news agency reported citing SOHR.
The clashes were in al-Mahsa, on the outskirts of al-Qalamoun, near the central province of Homs.
The IS, which proclaimed a caliphate in areas under its control in Iraq and Syria in late June, has previously carried out attacks in al-Qalamoun.
More recently, however, IS has been more active in central Syria and Damascus after suffering defeats in Aleppo and al-Hasakah in the north.
