The Russian foreign ministry claimed its expert findings show that the chemical weapon used in the chemical attack in Syria are similar to ones made by a rebel group. President Putin has warned the West against taking one-sided action in Syria.
Russian President Putin hinted that his country may approve a UN military operation in Syria, should further evidence of Assad's involvement be presented. However this more nuanced stance belies his ongoing links to the Assad regime, which Russia provides military and logistical support to.
President Vladimir Putin said Russia had provided some components of the S-300 air defence missile system to Syria but had frozen further shipments.
He suggested that Russia may sell the missile systems elsewhere if western nations attack Syria without UN Security Council backing.
In an interview with The Associated Press and Russia's state Channel 1 television, he said: "We have a contract for the delivery of the S-300s. We have supplied some of the components, but the delivery hasn't been completed. We have suspended it for now.
"But if we see that steps are taken that violate the existing international norms, we shall think how we should act in the future, in particular regarding supplies of such sensitive weapons to certain regions of the world."
Russian President Vladimir Putin said Russia may approve a military operation in Syria if Damascus is proven to have carried out chemical weapons attacks, but such an operation can only be conducted with UN approval.