The ruble looked set for its steepest one-day fall since the Russian financial crisis of 1998 on Monday, plunging more than 6 percent against the dollar before recovering to losses of around 4 percent.
Russia's central bank may have started to intervene on the foreign exchange market to curb ruble losses, three traders said on Monday.
"It may have been central bank," a trader at a Western bank told Reuters. The central bank declined to comment.
Early Monday, the ruble was down 3.9 percent at 52.45 against the dollar and 3.8 percent lower at 65.39 against the euro, hitting fresh record lows.
The dollar-based RTS stock index was down 3.1 percent to 944 points, having touched a five-year low of 930. In contrast the ruble-based MICEX, which benefits from a weaker ruble, was up 2.1 percent to 1,571 points, a 2014 high.
Oil benchmark Brent futures were hovering just above a five-year low, at $69.6 per barrel, weighed down by weak manufacturing data from China and last week's decision by OPEC not to cut oil production to support prices.