MOSCOW, Nov 30 (Reuters) - The rouble weakened towards 75 against the dollar on Tuesday, paring earlier gains as prices for oil, Russia's key export, fell near $70 barrel from above $80 in just three days, putting pressure on stocks indexes.
At 0704 GMT, the rouble was 0.4% weaker against the dollar at 74.92 , hovering away from its weakest level since May of 75.9225 that it hit on Friday.
Versus the euro, the rouble lost 0.7% to 84.74 .
The rouble has slipped from a multi-month peak of 69.21 versus the greenback hit in late October as it has come under selling pressure on Western concerns about possible Russian military intervention in Ukraine and the new coronavirus strain, Omicron.
"The new strain is likely to remain in the spotlight for the coming weeks, but investors are cautiously taking the view that Omicron is not going to result in much harm to global activity," VTB Capital said in a note.
Russian authorities are expected to share their view on the geopolitical risks, rouble, economy and the novel coronavirus at an annual investment forum "Russia Calling".
Central Bank Governor Elvira Nabiullina, Finance Minister Anton Siluanov and Economy Minister Maxim Reshetnikov are all due to speak there at the macroeconomic session before President Vladimir Putin takes the floor.
Brent crude oil , a global benchmark for Russia's main export, shed 1.9% to $71.98 a barrel, along with broader financial markets, after a media report cast doubt on the efficacy of COVID-19 vaccines against the Omicron variant.
Russian stock indexes were down.
The dollar-denominated RTS index fell 1.3% to 1,618.2 points. The rouble-based MOEX Russian index was 0.9% lower at 3,846.1 points, hovering at a distance from its all-time high of 4,292.68 it reached in mid-October.
Reporting by Andrey Ostroukh