MOSCOW: Rising oil prices helped the Russian rouble to firm on Wednesday after two successful treasury bond auctions, but gains were capped following the jailing of Kremlin critic Alexei Navalny.

A Russian court on Tuesday handed Navalny a 3-1/2-year prison sentence, straining ties with the West.

The rouble's gains were limited even as oil prices climbed higher. It traded at around 63.5 to the dollar when oil prices last hovered near current levels in February 2020.

By 1529 GMT, the rouble was up 0.3% against the dollar at 75.99 and had gained 0.5% to trade at 91.29 versus the euro.

Brent crude oil, a global benchmark for Russia's main export, was up 2% to $58.61 a barrel, a near one-year high.

"There is another complication for the stock market and the rouble in the face of yet another case against one of the opposition politicians who European and US embassies defend," said Otkritie brokerage, without using Navalny's name.

Russia's finance ministry said it would slash its foreign currency buying in February to 2.4 billion roubles ($31.6 million) worth of FX a day, a near three-fold decrease on the previous month.

"The finance ministry's unexpected (for the market) reduction in FX purchases in February will be a pleasant surprise for the rouble, given the heightened volatility of recent days and the impact of domestic political events," said Dmitry Polevoy, head of investment at Locko-Invest.

The finance ministry sold almost 20 billion roubles at two OFZ bond auctions on Wednesday, but cancelled a third due to a lack of bids. These bonds are popular among foreign investors for their lucrative yields.

Russian stock indexes were falling.

The dollar-denominated RTS index was down 0.8% to 1,387.8 points. The rouble-based MOEX Russian index was 0.3% lower at 3,348.7 points.