DAVID Cameron has accused Russia of supporting “the butcher” President Bashar al-Assad rather than fighting terrorism in Syria.

The Prime Minister said that Vladimir Putin's forces were not discriminating between Daesh (also known as Islamic State, Isis or Isil) and moderate opposition forces who have been engaged in a bloody civil war against Assad.

Cameron said: "It's absolutely clear that Russia is not discriminating between Isil [Daesh] and the legitimate Syrian opposition groups and, as a result, they are actually backing the butcher Assad and helping him and really making the situation worse.

"Rightly, they have been condemned across the Arab world for what they have done and I think the Arab world is right about that.

"But we should be using this moment now to try to force forward a comprehensive plan to bring political transition in Syria because that is the answer for bringing peace to the region."

American President Barack Obama has said Russia's strikes are "only strengthening" the Daesh position. Moscow, however, insists its air strikes – which began on Wednesday – are targeting Daesh, and that its aircraft had hit Daesh command centres and arms depots.

Russian officials claim targets included the Daesh stronghold of Raqqa, but also Aleppo, Hama and Idlib – provinces with little Daesh presence.

But Syrian opposition and others have suggested non-Daesh rebels are bearing the brunt of the attacks.

At least 39 civilians, including eight children, have been killed in Russian air strikes in Syria since Wednesday, according to information released by the Syrian Observatory for Human Rights. Some 14 fighters are also said to have been killed.

Cameron's comments echo the outspoken criticism of Russia's intervention by Defence Secretary Michael Fallon, who said the "vast majority" of strikes since President Putin began the action had not been aimed at Daesh jihadists but were instead "killing civilians" and the Free Syrian forces rebelling against Assad's regime.

Fallon said intelligence suggested Moscow had mostly been targeting forces fighting President Bashar al-Assad rather than Daesh militants.

He claimed only one in 20 raids had hit Daesh targets and said the "vast majority" were killing civilians and Free Syrian forces fighting Bashar Assad's forces.

Fallon said: "We're analysing where the strikes are going every morning. The vast majority are not against IS [Daesh] at all.

"Our evidence indicates they are dropping unguided munitions in civilian areas, killing civilians, and they are dropping them against the Free Syrian forces fighting Assad. [Putin is] shoring up Assad and perpetuating the suffering."

Fallon denied that Russia's involvement had left Europe and the US looking weak. "I don't accept he [Putin] has outmanoeuvred us. He has complicated the situation in Syria. But we're not powerless."

He indicated that the changed circumstances would not prevent the Government pressing ahead with making the case to extend the RAF's strikes against Daesh from Iraq into Syria, adding that it would be "morally wrong" not to target Daesh in Syria. "We can't leave it to French and Australian, American aircraft to keep our own British streets safe," he said.

Cameron has been expected to extend British air strikes from Iraq into Syria. However, following a defeat of his attempt to intervene in the country’s civil war in 2013, he said that any military action would only take place with the backing of MPs.

Labour said it may support strikes against Daesh in Syria, however, that was before Jeremy Corbyn became leader.

The SNP has said it will oppose military intervention.

President Obama also said the Russian bombing campaign is driving moderate opposition underground.

He told a White House news conference: "The problem here is Assad and the brutality that he's inflicted on the Syrian people, and it has to stop.

"We're not going to co-operate with a Russian campaign to destroy anyone who is disgusted and fed up with Assad.

"From their [Russia's] perspective, they're all terrorists. And that's a recipe for disaster."

But Putin has argued that his country's operation in Syria is designed to prevent the type of state implosion that took place in Libya after Nato's intervention in 2011.