US Secretary of State John Kerry is in Moscow for talks to try to bridge gaps with Russia over the political process to end Syria’s civil war.
He is now in talks with Foreign Minister Sergei Lavrov and will later meet President Vladimir Putin.
The US and Russia have long disagreed on what role Syrian President Bashar al-Assad should play in the process.
The US wants Mr Assad to stand down but Russia says only the Syrian people can decide his fate.
Ahead of the talks, the Russian foreign ministry attacked US policy, accusing Washington of “dividing terrorists into good and bad ones”.
Russia has been carrying out air strikes it says target position of the Islamic State (IS) group in Syria, but the US accuses Russia of bombing moderate rebels to shore up its ally President Assad. Moscow denies the allegations.
A US-led coalition has been targeting IS militants in Syria since September 2014 and does not co-ordinate its raids with the authorities in Damascus.