"Russia severely condemns the attack on Syria where Russian military are helping the lawful government in the fight with terrorism," the Kremlin said in a statement, its first reaction to the strikes.

Moscow also said it was calling an emergency session of the United Nations Security Council, where it is a permanent member, to discuss the "aggressive actions" of the US and its allies.

"Without the sanction of the UN Security Council, in breach of the UN charter and the norms and principles of international law, an act of aggression was committed against a sovereign state," the Kremlin said.

Russia said that the Western powers "cynically" carried out military action hours before a team from the Organisation for the Prohibition of Chemical Weapons was set to begin an investigation into the suspected chemical weapons attack in the town of Douma in Eastern Ghouta that sparked the intervention by the US and its allies.

The current escalation of the situation in Syria "has a destructive effect on the whole system of international relations," the Kremlin said.