Feb 13 (Reuters) - The Russian rouble slipped to a nine-month low against the U.S. dollar on Monday, continuing a downward slide despite huge currency interventions by the Russian government.

At 1215 GMT the rouble was down 0.4% against the dollar at 73.66, its weakest reading since April 2022. The currency had also lost 0.2% against the euro to trade at 78.59 and had weakened by 0.3% against the Chinese yuan to 10.78.

The Russian government has been selling 8.9 billion roubles ($121.83 million) of foreign currency per day to plug a budget deficit that has soared because of lower oil and gas revenues.

Russia's central bank on Friday held interest rates at 7.5%, but signalled it was preparing to raise rates in the coming months and expressed concern over the government's widening gap between its spending commitments and incoming tax revenue.

At the end of last week the rouble slid through 73 against the dollar for the first time since last April, with analysts expecting the currency to remain under pressure until exporters begin converting foreign currency earnings into roubles to pay local tax liabilities at the end of the month.

The government's surprise plans for a "voluntary" windfall tax on businesses and a 500,000 barrel per day cut in oil production from March have highlighted the pressures facing the Russian economy, analysts said.

"The rouble remains hostage to geopolitical risks, 'voluntary' contributions and also uncertainty over Russia's budget deficit - an increase of which may explain the fall in the rouble against the dollar and Chinese yuan to new lows this year," analysts at BCS Express wrote on Monday.

Expectations for weaker energy revenue were also weighing on the Russian currency after the central bank cut its Urals oil price forecast on Friday. The bank dropped its projected average price for the rest of the year to $55 a barrel, down from its previous forecast of $70.

Russian stock markets were mixed.

The dollar-denominated RTS index eased by 0.2% to 970.5 points while the rouble-based MOEX Russian index was up 0.2% at 2,267 points.

For Russian equities guide see

For Russian treasury bonds see (Reporting by Jake Cordell Editing by Toby Chopra and David Goodman)