Speaking to Rouhani by telephone the day after US-led strikes on suspected chemical weapons facilities, Putin said "if such actions, carried out in violation of the United Nations Charter, are repeated, that would inevitably provoke chaos in international relations," according to a statement from the Kremlin.

The two leaders "found that this illegal action seriously damaged the prospects of a political settlement in Syria," the statement said.

The United States, France and Britain on Saturday launched strikes against Bashar al-Assad's government a week after an alleged chemical attack in the Syrian city of Douma, just east of the capital Damascus.

Putin denounced on Saturday "with the utmost firmness" the strikes which he described as "an act of aggression against a sovereign state which is at the forefront of the fight against terrorism".