The MICEX index fell 2.7 percent to 1,299 points by late afternoon in Moscow. The ruble was down 0.9 percent against the U.S. dollar at 31.2 rubles.
The Russian markets' drop has been more severe than other European emerging economies over the past two weeks because of the country's dependency on oil prices, which have fallen 12 percent this month. Oil prices, in turn, have fallen on fears Greece may leave the euro currency union, causing turmoil in European markets.
Uncertainty about the makeup of Russia's new government has also been fueling investor anxiety.
The Russian Central Bank's chief said Wednesday that capital outflows remain a problem. More than $42 billion left the country in the first four months of the year. While that is half of the amount that left the country in the same period last year, it is still uncomfortably high and shows unease among investors.
Officials predicted that the outflows would decrease this year and blamed worries over political instability in Russia linked to the December parliamentary and the March presidential elections.