Intense fighting between pro-regime forces and opposition fighters in Syria's northwestern Idlib province killed at least 39 fighters overnight, the Syrian Observatory for Human Rights said Thursday.
The violence, which saw air strikes, shelling and ground combat, further buried a ceasefire announced by Russia on Sunday in Idlib, the last major opposition bastion in the country.
Regime and allied forces took two villages in their advance towards the key town of Maaret al-Numan, the Observatory said.
According to the Britain-based war monitor, the fighting flared late on Wednesday in areas south of Maaret al-Numan, the key target of the Syrian regime's latest military offensive.
At least 22 anti-government fighters were killed, most of them members of Hayat Tahrir al-Sham.
Seventeen regime troops and allied fighters were also killed in the fighting, said Rami Abdel Rahman, the head of the Observatory.
He added that regime forces were now just seven kilometers from Maaret al-Numan.
Nearly nine years into the conflict, protests against the government are still held in some of the province's towns.
In the city of Idlib itself, 18 civilians were killed in airstrikes on Wednesday, shattering the truce brokered by Moscow and Ankara.
