MOSCOW (Reuters) -The Russian rouble slumped to an eight-month low against the dollar on Thursday, struggling under the weight of expectations that sanctions on Russian oil and gas may limit export revenues.

By 0717 GMT, the rouble was 0.9% weaker against the dollar at 72.83, its weakest point since April 27.

It lost 0.7% to trade at 76.93 versus the euro and shed 0.6% against the yuan to 10.31.

The rouble has now lost the key support of a month-end tax period that usually sees exporters convert foreign currency revenues into roubles to pay domestic liabilities, while recovering imports have combined with falling exports to also exert pressure.

"The fundamental factor in the form of the change in current account parameters, where exports have decreased and imports risen, is putting noticeable pressure on the rouble's position," said Alfa Capital in a note.

, a global benchmark for Russia's main export, was down 0.9% at $82.5 a barrel.

President Vladimir Putin this week delivered Russia's long-awaited response to a Western oil price cap, signing a decree that bans the supply of and oil products from Feb. 1 for five months to nations that abide by it.

The rouble has now lost around 15% to the dollar since the price cap came into force on Dec. 5.

Russia's economy is also on shaky ground heading into 2023. November economic data on Wednesday gave signs that a labour shortage linked to Putin's late September partial mobilisation order was hurting growth prospects.

Russian stock indexes were mixed.

The dollar-denominated RTS index was down 0.8% to 926.5 points. The rouble-based MOEX Russian index was 0.1% higher at 2,141.5 points.

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