Russia has criticized Western efforts to expand a planned United Nations probe into the use of chemical arms in Syria.
In a statement, Russia's Foreign Ministry voiced anger over a UN letter, which told Damascus that it intended to broaden the investigation beyond the incident in late March near Aleppo.
Western countries are pushing for investigations into rebel claims about the use of chemical weapons.
The Syrian opposition has accused President Bashar al-Assad's regime of carrying out all chemical attacks. But the Russian statement compared the move to the buildup ahead of the U.S. invasion of Iraq.
Moscow says the UN probe announced last month should only focus on Syrian government allegations that rebels used chemical arms near Aleppo.
Moscow has previously used its veto to blunt Western pressure on the Assad regime.
Based on reporting by Reuters and ITAR-TASS