By Alexander Kolyandr

MOSCOW--Russian gold and foreign-exchange reserves in the past week fell to their lowest level since early March 2010, as the Bank of Russia had to spend its reserves to support the ruble, central bank data showed Thursday.

Russia's reserves, still the world's fourth largest, fell $4.7 billion in the week to Oct. 24 to $439.1 billion.

In the four weeks to Oct. 24 the central bank's reserves were depleted by $18 billion. The figure is close to the overall amount of funds that the central bank has spent since early October to slow the ruble's depreciation.

After trading close to its all-time lows, the ruble sharply recovered Thursday.

Write to Alexander Kolyandr at alexander.kolyandr@wsj.com