The Britain-based Syrian Observatory for Human Rights said jihadist group Hayat Tahrir al-Sham (HTS) and allied factions launched a surprise attack on the Syrian army in the northern province of Aleppo on Wednesday.
The toll "in battles ongoing for the past 24 hours has risen to 132, including 65 fighters from HTS", 18 from allied factions "and 49 members of regime forces", said the Observatory, which relies on a network of sources inside Syria.
Some of the clashes, in an area straddling Idlib and Aleppo provinces, are less than 10 kilometres (six miles) southwest of the outskirts of Aleppo city.
HTS, led by Al-Qaeda's former Syria branch, controls swathes of much of the northwest Idlib area and slivers of neighbouring Aleppo, Hama and Latakia provinces.
An AFP correspondent reported heavy, uninterrupted clashes east of the city of Idlib since Wednesday morning, including air strikes.
A military statement carried by state news agency SANA said that "armed terrorist organisations grouped under so-called 'Nusra terrorist front' present in Aleppo and Idlib provinces launched a large, broad-fronted attack" on Wednesday morning.
It said the attack with "medium and heavy weapons targeted safe villages and towns and our military sites in those areas".
The army "in cooperation with friendly forces" confronted the attack "which is still continuing", inflicting "heavy losses" on the armed groups, the military statement said, without reporting army losses.
