File photo of British Prime Minister David Cameron.
Russia is backing "butcher" President Bashar al-Assad with airstrikes that are often not aimed at Islamic State (IS) fighters in Syria, Britain's Prime Minister David Cameron said today.
Cameron said Russian forces were "making the situation worse" as they pressed a bombing campaign in the IS stronghold for a fourth day.
His comments came as British intelligence forces observed that only one in 20 Russian airstrikes were hitting IS targets, according to Britain's defence minister.
"It's absolutely clear that Russia is not discriminating between ISIL 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," said Cameron, using an alternative acronym for IS.
"They have been condemned across the Arab world for what they have done and I think the Arab world is right about that."
Repeating calls for regime change in Syria, the British prime minister added: "We should be using this moment now to try to force forward a comprehensive plan to bring political transition... because that is the answer for bringing peace to the region."
Cameron's comments, delivered ahead of his Conservative Party's annual conference in Manchester, northern England, echo those of his defence minister, Michael Fallon, published today in the Sun newspaper
British intelligence services observed that only five per cent of Russian air strikes had attacked the IS group, with most "killing civilians" and Free Syrian forces fighting Assad, Fallon told the tabloid.
He said that Russia's intervention had further "complicated" the crisis, while suggesting that Britain should extend its own bombing campaign -- currently only operational against IS in Iraq -- to Syria.
"We're analysing where the strikes are going every morning," he told the paper. "The vast majority are not against IS at all."
The United States has also accused the Kremlin of trying to buttress Assad, with President Barack Obama describing the airstrikes that began on Wednesday as "a recipe for disaster".