Having posted its biggest one-day gain in three months on Wednesday, the rouble was up 0.6 percent to 66.62 against the dollar as of 0715 GMT.

After sliding to this month's lows of 68.28 versus the dollar this week, the rouble regained ground on media reports that the United States might not have enough time to impose fresh sanctions against Moscow by the end of this year.

This boosted demand for Russian treasury bonds, known as OFZs, and let the finance ministry sell all OFZ bonds on offer at weekly auctions on Wednesday.

Yields on 10-year OFZs bonds, which move inversely with their prices, slumped to 8.69 percent from levels of above 9 percent a day before.

Demand for the bonds is seen as a gauge of market sentiment, given lingering uncertainty about whether Washington would impose sanctions on holdings of Russian state debt.

Month-end local taxes, which usually prompt export-focused companies to convert dollars to pay taxes at home, together with higher oil prices also supported the rouble.

Brent crude oil, the global benchmark for Russia's main export, was up 0.1 percent at $66.17 a barrel. This week it fell to $64.16, its lowest level since March.

Versus the euro, the rouble was 0.6 percent stronger at 75.54.