MOSCOW: The rouble weakened on Tuesday, heading back towards the more than one-month low hit in the previous session, as the fallout from the arrest of Kremlin critic Alexei Navalny continued to weigh on Russian assets.

At 0746 GMT, the rouble was 0.4% weaker against the dollar at 75.66, near a more than one-month low of 75.8675.

It lost 0.2% to trade at 91.63 versus the euro.

Police detained more than 3,700 people and used force to break up rallies across Russia on Saturday as tens of thousands of protesters ignored extreme cold and police warnings to demand Navalny be freed from jail where he is serving a 30-day stint for alleged parole violations that he denies.

More protest action has been scheduled for Sunday.

"Few markets look convincing, least of all Russia, with oil demand concerns and recent news-flow increasing the country's risk profile," said BCS Global Markets.

The European Union on Monday said it would refrain from fresh sanctions on Russian individuals if the Kremlin releases Navalny after 30 days.

In the absence of positive news on US fiscal stimulus, hopes of a possible delay to the recovery package were hampering the rouble and other emerging market currencies, Sberbank CIB analysts said in a note.

The rouble could weaken to 75.8 versus the dollar, they added.

Domestically, the rouble lost some support as the peak of a month-end tax period that generally prompts export-focused companies to convert their foreign currency into roubles to meet local liabilities passed.

Brent crude oil, a global benchmark for Russia's main export, was down 0.5% at $55.61 a barrel, pushing Russian stock indexes lower.

The dollar-denominated RTS index was down 0.2% to 1,408.6 points.

The rouble-based MOEX Russian index was 0.5% lower at 3,381.8 points.