BEIRUT — Syrian regime air strikes and artillery fire on Tuesday killed 23 civilians in the last major opposition bastion in the northwest of the country, a war monitor said.

The militant-held region of Idlib is supposed to be protected by a months-old ceasefire deal to prevent a broad regime offensive, but deadly bombardment has continued.

The Britain-based Syrian Observatory for Human Rights said around 30 were wounded overall, including some in a serious condition.

It said regime artillery fire killed seven civilians from the same family in the village of Talmanas, adding that the wife and three children of a member of the White Helmets rescue organization were killed in the village of Badama.

On its Twitter account, the White Helmets — a volunteer group that responds to bombings in rebel-held areas — posted a video of a volunteer apparently pulling the lifeless bodies of his family from the rubble of a building.

In the village of Maasaran, regime air strikes killed a further six civilians.

A photographer on site saw a pool of red blood and clothes strewn on the pavement by a shop whose window had been shattered.

"That's the regime for you," a resident said, as he helped a shopkeeper pick up some items of clothing.

Pro-government bombardment also led to four other civilians losing their lives in other parts of the bastion, the Observatory said.

The Idlib region, which is home to some three million people including many displaced by Syria's civil war, is controlled by the country's former Al-Qaeda affiliate.

The Damascus regime has repeatedly vowed to take back control of it.

Pro-government forces launched a blistering offensive against the region in April, killing around 1,000 civilians and displacing more than 400,000 people from their homes.

Moscow announced a ceasefire in late August, but the Observatory says deadly bombardment and skirmishes have persisted.

It says more than 250 civilians have been killed in the region since the deal.

Syria's war has killed over 370,000 people and displaced millions from their homes since beginning in 2011 with the brutal repression of anti-government protests. — AFP