Russia's rouble strengthened on Friday, paring some of the losses sustained in Thursday's slump to a more than 15-month low past 93 against the dollar, with the currency under pressure from domestic political concerns and strong FX demand.

Capital controls have helped insulate the rouble against geopolitics during the more than 16 months since Russia invaded Ukraine, but mercenary leader Yevgeny Prigozhin's aborted march towards Moscow on June 24 has reverberated through markets and raised questions about President Vladimir Putin's grip on power.

At 0739 GMT, the rouble was 0.5% stronger against the dollar at 91.86, after dropping to 93.85 in the previous session, its weakest point since March 28, 2022.

It was unchanged at 100.04 versus the euro and shed 0.6% against the yuan to 12.65.

Russian authorities have sought to project an aura of calm, but at the peak of Thursday's losses, the rouble was down about 25% year-to-date.

Alor Broker's Alexei Antonov said he expected a corrective strengthening of the rouble as it had been trading in a downtrend since the autumn.

Falling export revenues combined with recovering imports has gradually put pressure on the rouble in the past year but that slide sped up rapidly after Prigozhin's armed mutiny as demand for foreign currency starkly outweighed supply.

Brent crude oil, a global benchmark for Russia's main export, was up 0.6% at $77.01 a barrel.

Russian stock indexes were mixed.

The dollar-denominated RTS index was down 0.3% to 968.6 points. The rouble-based MOEX Russian index was 0.2% higher at 2,825.3 points. (Reporting by Alexander Marrow; editing by Robert Birsel)