The sanctions theme came into the spotlight again after U.S. Republican and Democratic senators introduced legislation on Wednesday seeking to deter Russia from meddling in U.S. elections, threatening stiff sanctions on its banking, energy and defence industries and sovereign debt.

The rouble showed limited reaction to yet another threat to slap on new sanctions, slowly heading towards the level hit on Monday, its weakest since March 12.

As of 0751 GMT, the rouble was 0.2 percent weaker at 65.38  per dollar and also lost 0.2 percent to trade at 73.46 versus the euro.

"A stronger rouble reaction to the sanctions theme is possible if such legislation will be considered more actively," analysts at Nordea Bank said in a note.

Shrugging off the risk of more sanctions, investors snapped up Russia's OFZ treasury bonds at the finance ministry's auctions on Wednesday.

The ministry sold 83 billion roubles ($1.3 billion) worth of such bonds, its second best result so far this year, indicating demand for Russian assets remains strong given Russia's  investment grade credit ratings and high yields.

Brent crude oil, a global benchmark for Russia's main export, slid 0.3 percent at $69.12 a barrel but hovered near its 2019 peak of $69.96 hit the day before.

Russian stock indexes were down. The dollar-denominated RTS index was down 0.4 percent at 1,219.3 points, while the rouble-based MOEX Russian index was 0.1 percent lower at 2,530.1 points.