MOSCOW: The Russian rouble firmed on Tuesday, buttressed by oil prices surging to their highest since February last year, but market players were focused on a court hearing that could see prominent Kremlin critic Alexei Navalny handed a significant jail term.

A Russian court was set to decide whether to jail Navalny, a fierce critic of President Vladimir Putin, for up to three and a half years.

The rouble was 0.7% stronger at 75.59 against the dollar as of 1440 GMT and up 0.9% to 90.93 versus the euro with the court hearing underway.

Brent crude oil, a global benchmark for Russia's main export, was up 2.5% at $57.75 a barrel, reaching an almost one-year high.

"Today, taking into account the external positives, the rouble could try to strengthen, and only news from Navalny's trial, which the world is following, can hold it back," said Dmitry Polevoy, head of investment at Locko-Invest.

Navalny was detained last month on his return from Germany where he was recovering after a suspected poisoning. His detention sparked mass street protests across Russia.

The political unrest is a headache for Putin, 68, who has dominated Russian politics for over two decades. The case has set off new talk of Western sanctions on Russia and raised tensions as U.S. President Joe Biden launches his administration.

The rouble looks undervalued given the fundamental factors but its price envisages a geopolitical premium which can pressure the Russian currency, Otkritie bank said.

On the upside, the Russian economy shrank by just 3.1% amid the COVID-19 pandemic in 2020, data showed late on Monday. While the sharpest contraction in 11 years, it was much shallower than predicted by analysts and the Russian government.

Russian stock indexes were climbing.

The dollar-denominated RTS index was up 2.7% to 1,400.6 points, while the rouble-based MOEX Russian index was 2.1% higher at 3,360.4 points.