Russian Foreign Minister Sergei Lavrov says America's Syria policy encourages the financing and supply of "terrorist organisations".
During a visit to Iraq on Thursday, Lavrov claimed US policy "encourages extremists who are financing terrorism and supplying terrorist organisations and groups with weapons".
"In the end, this will not result in anything except the escalation of the Syrian conflict," he said at a joint news conference with Iraqi Foreign Minster Hoshyar Zebari.
Moscow is one of the main backers of Syrian President Bashar al-Assad's regime, which is locked in a bloody conflict with rebels which has seen more than 140,000 people die since 2011.
The conflict has contributed to a year-long surge in violence in Iraq to levels not seen since 2008, when the country was just emerging from a brutal period of sectarian killings.
Lavrov's visit to Baghdad comes after peace talks between the Syrian government and opposition co-sponsored by Russia and the United States broke off last week, with no date set for a third round.
Washington has accused Moscow of not doing enough to make sure the Assad regime is fully committed to the talks, a charge Russia has rejected.
