Syria rebels say they spotted regime chemical weapons convoy, warn of imminent attack

A Turkey-backed rebel coalition in the Syrian province of Idlib has accused Damascus regime of preparing to carry out a chemical attack, Syrian news website Enab Baladi has reported.

The National Liberation Front said in a statement on Wednesday that it has spotted regime trucks carrying barrels loaded with what appears to be chemical materials arriving in the neighbouring province of Hama.

"The regime's Brigade 155 transported 10 barrels from Damascus overnight last week to the Salamiyah region," the statement said.

"The barrels were unloaded into warehouses in the town of Kitlun. They were then moved to another place unknown to us," it added.

The statement comes after Russia claimed rebels are preparing a chemical attack in Idlib province which will be blamed on Damascus and used as a pretext for Western powers to hit government targets in the war-torn country.

Moscow's accusation came after US President Donald Trump's national security adviser John Bolton this week said Washington will respond "very strongly" if Syrian President Bashar al-Assad uses chemical weapons in an offensive to retake Idlib, one of the last rebel-held provinces in the country.

Russian defence ministry spokesman Igor Konashenkov said in a statement that the jihadist group Hayat Tahrir al-Sham is "preparing another provocation of the 'use of chemical weapons' by Syrian government forces against the peaceful population of the Idlib province."

In April, the US, France and Britain launched joint missile strikes on Syrian targets in response to an alleged chemical weapons attack in the town of Douma that left scores dead.

Russian stuck by its ally Syria and angrily insisted the Douma attack was staged by the White Helmets volunteer rescue service.

Speculation is increasing that there could be a Russian-backed government assault on Idlib, one of the so-called "de-escalation" zones set up as a result of talks by Russia, Turkey and Iran last year.

The Syrian regime has repeatedly used chemical weapons during the war against civilians and then claimed the attacks were staged by Western-backed rebel groups.