By Andrey Ostroukh 

MOSCOW--The Russian ruble weakened to new lows in early trading on Friday, hit by a drop in oil prices after OPEC members rejected calls for drastic action to cut their oil output.

Responding to the currency's sharp decline, the Bank of Russia said it would extend limits on currency swaps in an effort to stabilize the ruble.

The ruble touched an all-time low of 49.90 versus the dollar in the first minutes of trading on Moscow exchange, before recovering slightly to 49.57. This takes the ruble's year-to-date depreciation against the greenback to 34%.

The decision by the Organization of the Petroleum Exporting Countries to keep its production ceiling unchanged sent Brent crude prices below $72 per barrel for the first time since mid-2010. The slump in oil prices threatens to further slow Russia's embattled economy as around 50% of the country's annual budget revenue stems from oil and gas exports.

Against the euro, the ruble eased to 62.03 before recovering slightly to 61.72.

The Bank of Russia has allowed the ruble to float freely against the dollar and euro since early November, having previously intervened on currency markets to stem its loss in value.

Russia's central bank had set a daily limit of $2 billion for currency-swap operations, where banks receive rubles from the regulator using dollars and euros as collateral. This tool drew demand only recently after the central bank withdrew a large chunk of rubles from the interbank market as a result of $30 billion intervention in October.

By extending the limit for the next two weeks on Friday, the central bank said it hopes to deter speculators from betting on a weaker ruble.

The central bank had warned that it might intervene in the markets in future to prop up the ruble, if it deemed it necessary for the sake of Russia's financial stability.

Write to Andrey Ostroukh at andrey.ostroukh@wsj.com