President Vladimir Putin has warned the United States against any military action on Syria without UN approval, saying it would be an aggression.

In an interview with the Channel 1 TV and posted on the Kremlin website on Wednesday, Putin reinforced his demand that the Obama administration needed approval from the UN Security Council before taking action.

"It must be presented to the UN Security Council if there is evidence that chemical weapons were used and by the government forces," he said ahead of a G20 summit in St. Petersburg.

Putin said Russia would take decisive and serious action over Syria, if clear evidence of the use of mass destruction weapons exists.

Meanwhile, he said Russia did not intend and would not engage in any conflicts in other countries.

He noted that Russia had delivered some components of S-300 air defense system to Syria according to a previous contract, "but the supplies have now been suspended."