Four killed as 'violent' air raids pound Syria's Idlib

Nearly 60 Russian air raids hit Idlib province near the Turkish border in less than three hours, the Syrian Observatory for Human Rights monitoring group said.

The Russian strikes and regime barrel bombing - dropping containers filled with explosive material - on south and southeastern areas of the province killed at least four civilians including two children, the Britain-based monitor said.

The raids targeted jihadist and rebel positions, some of which were empty and others in use, Observatory head Rami Abdel Rahman said.

An AFP correspondent in the southern village of al-Muntar saw huge clouds of grey smoke billow up above olive trees after a barrel bombing.

Women and children ran terrified across nearby fields, one woman appearing to clutch a baby in a blanket.

It was the "most violent" bombardment since August 10, when fierce bombardment killed at least 53 civilians including 28 children in Idlib and the neighbouring province of Aleppo, he said.

Idlib and nearby areas are largely controlled by Hayat Tahrir al-Sham, an alliance led by al-Qaeda's former Syrian affiliate, as well as rival rebels.

On Friday, Russian air strikes killed four hardline rebels and a shepherd in Idlib province, the Observatory said.

The spike in violence came after Russia, fellow regime ally Iran and rebel backer Turkey on Friday failed to immediately agree on a solution to avert an imminent government offensive.

While Iran and Russia back the regime of Bashar al-Assad, Turkey backs opposition fighters and has warned against an offensive on Idlib that could turn it into a "bloodbath".

During the talks on Friday, Iran's President Rouhani said fighting "terrorism" in Idlib and the rest of Syria was "an unavoidable part" of restoring stability to Syria.

Throughout the seven-year conflict, the Syrian regime and its allies have designated many of their rebel opponents as terrorists in order to legitimise brutal attacks on them.

President Bashar al-Assad's regime has upped its rhetoric on retaking control of Idlib and surrounding areas over the past month.

The United Nations fears a full-scale offensive could cause a humanitarian catastrophe involving tens of thousands of civilians. Three million people live in Idlib, at least half of whom have already been displaced from areas in Syria recaptured by the regime.

Assad's threats come after regime forces seized back areas around the capital Damascus and in the south from rebels and jihadists earlier this year.

More than 350,000 people have been killed and millions displaced since Syria's civil war started in 2011 with the brutal repression of anti-Assad protests.