By Andrey Ostroukh 

NEW YORK--The Russian ruble weakened to a record low Friday, as it continued to struggle under falling oil prices after OPEC members rejected calls for drastic action to cut their oil output.

The ruble touched a fresh low, with 50.03 rubles required to buy one dollar in afternoon trade during the New York session, before recovering slightly to 49.98. This takes the ruble's year-to-date depreciation against the dollar to 34%.

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 decision by the Organization of the Petroleum Exporting Countries to keep its production ceiling unchanged sent Brent crude prices below $70 per barrel in intraday trading for the first time since May 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 62.24 before recovering slightly to 62.16.

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