"This is a thoughtless, irresponsible step. It will inevitably lead to an increase in prices on the European energy market," the Russian foreign ministry said in a statement.
Russia is a key supplier of natural gas to EU states and has often been accused of using gas prices as a political weapon.
"The economies of Russia and the European Union are 'communicating vessels' and Brussels moving to 'third phase' sanctions will affect the economic situation in the EU no less than in Russia," said the ministry.
The EU yesterday announced its first so-called Phase 3 sanctions targeting sectors of Russia's economy, limiting the access of state banks to financial markets, banning future weapons sales, and restricting the sale of sensitive technology, in particular in the energy industry.
Russia also slammed Brussels for following Washington too much and its "inability to play an independent role in world affairs".