Late on Friday, Moody's Investor Service raised Russia's rating to Baa3 from Ba1, saying the policies enacted in recent years will strengthen the country's already robust public finances and will help it withstand possible US sanctions against Moscow.

"The upgrade is likely to support the rouble and OFZs, which could be easily limited by fear of upcoming US sanctions," said Vladimir Miklashevsky, senior economist and trading desk strategist at Danske Bank in Helsinki.

At 0701 GMT, the rouble was 0.4 percent stronger against the dollar at 65.56 and had gained 0.3 percent to trade at 74.25 versus the euro.

Domestic investors will remain cautious on the stock market and the rouble until clarity around US sanctions emerges, Otkritie Brokerage said in a note.

Russian stock indexes opened higher. The dollar-denominated RTS index was up 0.7 percent to 1,207.5 points, while the rouble-based MOEX Russian index was 0.4 percent higher at 2,513.3 points.