An employee counts Russian ruble banknotes at an office in Siberia in December, 2014.

Moody's Investors Service could cut the ratings on up to 16 Russian banks, the credit ratings agency warned on Tuesday.

"With a much more pronounced weakening in Russia's economic outlook in the next two years than previously anticipated, financial institutions now face more significant pressures on their funding costs, asset quality and profitability in the medium term," Moody's said in a report out Tuesday.

The agency forecast the Russian economy would shrink by 5.5 percent in 2015 and 3 percent in 2016.

The Russian ruble has tumbled nearly 70 percent against the U.S. dollar since the start of the year. On Monday, Russia's central bank said it would provide a mid-size bank with up to 30 billion rubles ($530 million) to prevent its bankruptcy, in the first bailout of its kind during the current ruble crisis.

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