The rouble was little changed at 64.23 against the dollar at 0740 GMT, hovering near its strongest level since March 26 of 64.05 it hit on Monday. Versus the euro, it was stable at 72.64.

"The Russian currency is starting to get support from the upcoming tax period as well as OFZ placements," Otkritie Brokerage said in a note.

Tax payments usually prompt export-focused companies to convert their foreign currency to meet duties at home. This month, such payments could amount up to 2.2 trillion roubles ($34.27 billion), according to analysts surveyed by Reuters.

The finance ministry is in focus on Tuesday as it will announce details of Wednesday's auctions of OFZ bonds, which enjoyed strong demand in the past few weeks.

Demand for these rouble-denominated bonds is usually seen as a barometer for market attitude towards Russian assets amid lasting risks of possible US sanctions against holdings of Russian debt.

To fulfil the borrowing plan for this year the finance ministry needs to raise at least 48 billion roubles ($747.6 million) a week, which it has easily managed to do at the last five auctions, analysts at Rosbank said in a note.

Brent crude oil, a global benchmark for Russia's main export, was down 0.1 percent at $71.08 a barrel, trading near 2019 highs and supporting Russian stocks.