MOSCOW—A decrease in global oil prices to levels last seen in 2010 sent the Russian ruble lower on Friday, but the recent decision by the Bank of Russia to allow the currency’s exchange rate to float freely seemed to have a limiting impact on its losses.

Falling oil prices, which started late July, fanned downside pressure on the ruble, battered by Russia’s flagging economic growth and Western sanctions. The country is now preparing to withstand a “catastrophic decline” in oil prices, President Vladimir Putin said in an interview to the state-run news agency TASS on Friday.

The ruble eased 0.7% to 47.13 versus the dollar by 1200 GMT, moving toward its weakest-ever level of 48.50 reached last week. Hit by a drop in Brent crude prices below $80 a barrel for the first time since September 2010, the ruble’s loss on Friday was relatively small compared to the volatility of the past few weeks.

Following a gradual weakening of the ruble to record lows in October, which prompted the central bank to spend some $30 billion to ease pressure on the currency, the Bank of Russia said on Monday that it would allow the rate to float freely in the market, eliminating its regular interventions. The central bank has warned however that it may carry out massive interventions at any level to deter speculators from betting against the ruble.

“Speculators are not opening new positions now, volatility is of cosmic proportions,” said Dmitry Stadnik, chief forex trader at Rosbank, the Russian subsidiary of French bank Société Générale .