The most senior British officer in the fight against Islamic State of Iraq and the Levant (Isil) has denounced Russian claims that Britain and the US are about to stage a chemical attack in Syria.

Major General Felix Gedney, the Deputy Commander of the international military force to defeat Isil, dismissed as "absolutely ridiculous propaganda" suggestions Britain and the US are about to launch chlorine-loaded missiles.

"The UK is a proud coalition member with a proven track record [to defeat Isil]," Maj Gen Gedney said in a tweet.

"All [coalition] members condemn the use of chemical weapons," he added.

Earlier Major General Igor Konashenkov, the Russian defence ministry's spokesman, said that American cruise missile ships working in conjunction with "British secret services" will target the settlement of Kafr Zayta, to the south of Idlib, "as a pretext for missile strikes by the West and the United States".