Both Russia and the United States demanded ceasefires in the long-running civil war so that the fight could be concentrated against Islamic State of Iraq and the Levant (Isil) – but each on their own, conflicting terms.

But the Gulf states, led by Saudi Arabia, staged their own intervention, saying they were committed to sending ground troops to the country. Their favoured rebel groups have been pulverised by Russian air raids and driven back on the ground by Iranian-supplied pro-regime troops.

They said their declared target was Isil. But the presence of troops from Gulf states which have funded the Syrian rebels would be taken as a hostile act by the Assad regime and its backers, and a sign that they were committed to staking their claim to a say in the final Syrian settlement.

Russia issued a stark warning of the potential consequences. “The Americans and our Arab partners must think well: do they want a permanent war?” its prime minister, Dmitry Medvedev, told Germany’s Handelsblatt newspaper in an interview due to be published on Friday but released on Thursday night.

“It would be impossible to win such a war quickly, especially in the Arab world, where everybody is fighting against everybody.

“All sides must be compelled to sit at the negotiating table instead of unleashing a new world war.”

Read more at The Telegraph