Russia is assessing the situation in Syria and is in constant contact with the Syrian authorities, Kremlin spokesman Dmitry Peskov said on Thursday.
The extent of Russian assistance to Damascus will depend on this assessment, Peskov added.
Syrian rebels have staged their biggest advance in years over the past week with the seizure of the city of Aleppo. On Thursday the rebels said they had started pushing into Hama, a major city where pro-government forces backed by intense Russian air strikes are trying to halt their offensive.
Russia is a key ally of Syrian President Bashar al-Assad and has provided him with military support since 2015 in the country's civil war.
"At the moment, we are closely monitoring what is happening in Syria. We are in constant dialog with our Syrian friends, with Damascus," Kremlin spokesman Dmitry Peskov told reporters.