Russian banks have borrowed too heavily on international markets, Russia’s top bank supervisor warned on Thursday, raising potential risks for the country’s consumer lending boom amid a global credit crunch.

Many Russian banks “have stuffed their vaults to the maximum with loans in foreign currencies”, said Gennady Melikyan, first deputy chairman of Russia’s central bank. “They could face certain difficulties” if the dollar continued to strengthen. But, he added, “We have about five times more [reserves] than we need to ensure the stability of our monetary system.”