A Syrian youth walks through rubble and debris in a building that was damaged by a reported government forces' airstrike in the village of al-Haraki in the northwestern Idlib province on Sunday. — Photo AFP

SURMAN, Syria — Two days of clashes between government 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 on 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 Hafez, one of those driven from his home and 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 government forces.

The Britain-based Observatory on Sunday put the death toll from fighting at 69 combatants since battles started the previous day.

At least 36 government forces were among those killed.

The Observatory said an attack led by Syria's former al-Qaeda affiliate on several government positions had initially sparked the fighting.

Overnight, the Syrian army backed by Russian warplanes launched a counter-push to reclaim territory it had lost in the battles, the war monitor said.

Government forces have since regained lost ground but violent clashes are ongoing, the Observatory said

Between late April and the end of August, Idlib was pounded ceaselessly by Syrian soldiers backed by Russian air power.

The Observatory estimates that nearly 1,000 civilians were killed in that period, and the UN says that more than 400,000 people were displaced.

A ceasefire announced by Russia in late August has reduced fighting, but air strikes and clashes increased in November.

According to the Observatory, more than 160 civilians and more than 460 fighters, including regime forces, have been killed since the deal went into effect.

On Sunday, the commander-in-chief of the Kurdish-led Syrian Democratic Forces said Russian troops would deploy in three key areas under its control.

"We have agreed on the deployment of Russian forces in Amuda, Tal Tamr and Ain Issa to secure safety and stability in the area," Mazloum Abdi said after a meeting with the chief of Russian forces in Syria.

Syria government troops had already deployed in the three areas in October to help Kurdish forces contain Turkey's invasion.

The war in Syria has killed more than 370,000 people and displaced millions since it erupted in 2011. — AFP