By Jonathan Davies
The Russian central bank has said it spent $4.53bn (£2.9bn) last week on boosting the rouble.
It takes the total for the year so far to more than $70bn.
It comes after The World Bank said the the Russian economy would shrink by 0.7% in 2015 if oil prices do not pick up.
Oil is Russia's biggest source of income, but prices have hit five-year lows of $67 this week. And Morgan Stanley yesterday said that prices could fall as low as $43 a barrel next year.
"The CBR [Central Bank of Russia] simply is not doing enough to convince the market that it is serious, using a pea-shooter in terms of current piecemeal intervention," said Standard Bank analyst Tim Ash in a note. "It will need to hike rates significantly to defend the rouble, or let the rouble further weaken."
The CBR already raised interest rates by 1.5% to 9.5% in October. But speculation is growing over another rate rise in an attempt to boost the rouble.
Following the news, the rouble fell by 0.9% against the US dollar to 54.25 roubles and lost 1.1% to 67.00 against the euro.
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