The US-led strike was denounced by Putin as an "act of aggression," and a "war crime" by Iran's Supreme leader Ayatollah Khamenei.

"Vladimir Putin, in particular, stressed that if such actions committed in violation of the U.N. Charter continue, then it will inevitably lead to chaos in international relations," the Kremlin statement said.

The United States, France and Britain launched over 103 missiles on Saturday night at three Syrian facilities in retaliation for a suspected poison gas attack in the city of Douma seven days prior. While the West has conclusively blamed the Assad government for the attack, serious questions have arisen over everything from Assad's motive, the type of nerve agent used, to the credibility of the first responders - an NGO known as the White Helmets who have a reputation for staging evidence.