Regime air strikes on Syria's last major opposition bastion killed 18 civilians on Saturday, a war monitor said, a day before a ceasefire is due to take hold. Six children were among the dead in the northwest province of Idlib, where a fresh ceasefire brokered by Russia and Turkey is expected to go into effect after midnight, according to the Syrian Observatory for Human Rights. Air strikes on the city of Idlib killed seven civilians, while separate raids on two towns near the provincial capital killed 11 others, the Britain-based war monitor said. In Idlib city, the bombardment hit near a cultural centre, according to the Observatory and an AFP correspondent in the area.

Scores of students, many of them crying, ran from the site of the blast in panic, the AFP correspondent said.

The bombardment surprised residents in a city that has been relatively free from the near-daily attacks that have hit the province's flash-point south, the correspondent added.

Less than 10 kilometres (six miles) away, regime air strikes hit a market in the town of Binnish, killing seven, according to the Observatory.

The market was mostly reduced to rubble, as thick white smoke from the strikes created a fog, according to an AFP correspondent there.

He saw men carrying what the apparently lifeless bodies of two children from the scene, as women and children wailed. One woman pressed two children to her chest as she screamed for help, he said.