Two days of clashes between regime forces and armed groups in Syria's last major opposition bastion have killed nearly 70 on both sides, undermining a months-long ceasefire agreement, a war monitor said Sunday.

The battles in the northwestern province of Idlib are "the most violent" there since a Russian-brokered ceasefire agreement went into effect in late August, said Rami Abdul Rahman, head of the Syrian Observatory for Human Rights.

Residents of affected villages fled north to escape the fighting, adding to the hundreds of thousands who have already flooded out of the province's violence-plagued south since fighting escalated earlier this year.

"I don't want to see my children trapped under rubble," said one of those driven from his home, Hafez, who escaped the flashpoint area along with his wife and three kids two days earlier.

On Sunday morning, clouds of smoke rose over the Maaret al-Numan region as warplanes pounded jihadists and allied rebels in positions they had recently recaptured from regime forces, said an AFP correspondent.

The Britain-based Observatory on Sunday put the death toll from fighting at 69 combatants since battles started the previous day. At least 36 regime forces were among those killed. The Observatory said an attack led by Syria's former Al-Qaeda affiliate on several regime positions had initially sparked the fighting.

Copyright Agence France-Presse, 2019