U.S. President Donald Trump's administration on Sunday lifted sanctions on aluminium giant Rusal and other companies linked to oligarch Oleg Deripaska, defying a Democratic-led push in the U.S. Congress to maintain the restrictions.

After outperforming the market on Monday, shares in Rusal  had dropped 6.2 percent to 29.18 roubles ($0.44) by 0743 GMT on Tuesday. The benchmark MOEX index was 0.4 percent lower at 2,466.3 points.

Russian assets remained vulnerable to a decrease in global risk appetite, and persisting worries over whether Washington will impose fresh restrictions, particularly on holdings of Russian state debt.

The finance ministry is in focus on Tuesday as it is set to publish parameters of its weekly auctions of OFZ treasury bonds due on Wednesday.

Tuesday also brings the start of a two-day U.S. Federal Reserve policy meeting, where Chairman Jerome Powell is widely expected to acknowledge growing risks to the U.S. economy as global momentum weakens.

The rouble was 0.1 percent weaker at 66.32 versus the dollar  and eased 0.2 percent to 75.91 against the euro .

The rouble lost support from month-end tax payments that ended on Monday and is now moving in line with other emerging market currencies.

The central banks' decision to resume from Feb. 1 buying of foreign currency that it put on hold last year, or so-called postponed FX purchases, is seen limiting the room for the rouble's appreciation despite relatively high oil prices.

"This could signify an end to rouble's appreciation bias despite seasonal current account strength," analysts at Rosbank said in a note, referring to the central bank's decision.