The rouble firmed 0.1 percent to 65.61 versus the dollar as of 0748 GMT, heading away from its weakest point this moth of 68.28 hit in mid-November.

Versus the euro, the rouble was unchanged ad 74.76 .

"The external background is neutral for the rouble for now," said Alexei Antonov, an analyst at Alor Brokerage.

"We do not yet see factors capable of driving the rouble beyond the 65 mark (against the dollar)," Antonov said.

He said the tax payment period was seen as supportive of the Russian currency, which usually gets a boost closer to the second half of every month when export-focused companies convert their dollar revenues to meet local tax duties.

This support is likely to last for a few more days even if a rally in other emerging market currencies proves to be short-lived, said analysts at Rosbank, subsidiary of Societe Generale.

Strong demand for government bonds at the finance ministry's auctions on Wednesday also supported the rouble, especially after the central bank said foreign buyers started buying into OFZ bonds again.

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

Russian stock indexes were mixed. The dollar-denominated RTS index was up 0.3 percent at 1,130.7 points, while the rouble-based MOEX Russian index shed 0.2 percent to 2,345.3 points.