Claims by the United States that Syrian President Bashar al-Assad has used chemical weapons against rebels have provoked a sharp response from top officials in Russia.
Calling the report "fabricated", Russian policymaker Alexei Pushkov said: "Information about the usage of chemical weapons by Assad is fabricated in the same way as the lie about [Saddam] Hussein's weapons of mass destruction [in Iraq]."
The chief of the Russian lower house of parliament's international affairs committee said the Obama administration "is going the same way" as the Bush era.
Earlier, the White House had said that the Syrian regime had used chemical weapons against opposition groups, a move Obama labelled as crossing the "red line", prompting Washington to consider "direct military support" to the rebels.
Russian Foreign Minister Sergei Lavrov has also criticised Washington's remarks on the use of chemical weapons.
"The regime, as the opposition is saying out in the open, is enjoying military success on the ground. What sense is there for the regime to use chemical arms -- especially in such small amounts?" Lavrov said during a joint press conference with his Italian counterpart Emma Bonino.
Syria has also attacked the US claim concerning chemical weapons.
"Pursuant to impudent practices that the United States has previously resorted to in order to justify its policies, the White House issued a statement full of lies on chemical weapons use in Syria and based on fabricated information," said a Syrian foreign ministry source, according to state-run SANA.
The source added: "While seeking banal means to justify the US President Barack Obama's decision to arm the Syrian opposition, the United States is practising a flagrant double-standard policy in dealing with terrorism."
The UK government has backed the Obama administration over the claims, but it is yet to take a decision on arming the rebels fighting the Assad regime.