Moscow: Russia said on Friday that US data on the Syrian regime`s alleged use of chemical weapons was "unconvincing", and warned Washington against repeating the mistake it made when invading Iraq after falsely accusing Saddam Hussein of stocking weapons of mass destruction.
The Kremlin`s top foreign policy adviser Yury Ushakov also said the US decision to provide military aid to Syrian rebels would damage international efforts to end a conflict that has left tens of thousands dead.
The Syrian war will take centre stage next week in Northern Ireland where global leaders -- including Russian President Vladimir Putin -- gather for a G8 summit.
Ushakov said US officials had recently presented Russia with new information about the alleged use of chemical weapons against rebels by Syrian President Bashar al-Assad`s forces.
"What was presented by the Americans does not look convincing to us," he told reporters.
"I would not want to make any parallels, I would not want to believe that this data can be similar to the situation with the vial that (US) secretary of state Colin Powell brandished at the famous Security Council meeting."
Ushakov was referring to a UN Security Council meeting in 2003 at which Powell held up a vial that he said could contain anthrax as he presented evidence of Iraq`s alleged arms programmes.
Those weapons, cited by George W Bush`s administration as the main motive for launching the US-led invasion of Iraq in 2003, never surfaced after the fall of the Baghdad regime.
The head of the Russian lower house of parliament`s foreign affairs committee went even further than Ushakov, bluntly accusing Washington of making up claims that Assad had used chemical weapons against the rebels.
"Information about Assad`s use of chemical weapons has been fabricated in the same place as the lies about (Saddam) Hussein`s weapons of mass destruction" in Iraq, Alexei Pushkov said on Twitter.
"Why would Assad use sarin `in small amounts` against the fighters? What is the sense?! In order to prompt outside intervention? It makes no sense," he wrote.
Ushakov said the chances of holding a Syrian peace conference that Russia and the United States proposed jointly in May would be hurt by Washington`s plans to provide military support for the opposition.
"Of course, if the Americans truly decide and in reality provide more large-scale assistance to rebels, assistance to the opposition, it won`t make the preparation of the international conference easier," said Ushakov.
Asked if the US decision to start arming the rebels would prompt Russia to proceed with the delivery of S-300 anti-aircraft missiles to the Damascus regime, Ushakov said: "We are not talking about this yet. We are not competing on Syria."
Putin has said that Russia has signed a contract for the S-300s` delivery without making any shipments yet.