Syrian government and opposition factions say Syrian armed groups have launched a large-scale attack on areas controlled by government forces, setting off fierce clashes for the second day. The offensive, during which rebels expelled troops from over a dozen villages in Western Aleppo, follows weeks of simmering violence in the area where activists said government and allied Russian forces have stepped up their bombardment of parts of the last remaining stronghold of the opposition. Syria’s armed forces said Thursday the offensive was led by Hayat Tahrir al-Sham, or HTS, which controls much of northwest Syria and is in violation of a de-escalation agreement. It said the attacks are ongoing and have targeted a number of villages and military bases.