(Updates prices, adds BCS comment) MOSCOW, March 9 (Reuters) - The Russian rouble firmed past 88 against the euro to a six-month high on Tuesday, supported by rising oil prices, but restrained by the lingering threat of more sanctions against Moscow. By 1254 GMT, the rouble had gained 0.5% against the euro to 87.99, earlier hitting 87.8700, its strongest mark since Sept. 2, 2020. Against the dollar, the rouble strengthened 0.3% to 73.99. Brent crude oil, a global benchmark for Russia’s main export rose 0.8% to $68.67 a barrel. The rouble should remain between 73 and 75 against the greenback in the near future, BCS Global Markets in a note, as geopolitical risks weigh on the Russian currency despite rising oil prices. The Kremlin on Tuesday said it was alarmed by a report in the New York Times that said the United States was planning a series of covert counterstrikes on Russian networks in response to the hacking of SolarWinds software that U.S. officials say was conducted by Russia, something Moscow denies. Riskier assets gained support on Monday after U.S. Treasury Secretary Janet Yellen said President Joe Biden’s coronavirus aid package would provide enough resources to fuel a “very strong” U.S. economic recovery, and noted “there are tools” to deal with inflation. However, revised data on Tuesday showed a deeper euro zone economic contraction than previously thought in the fourth quarter of 2020. Finance Minister Anton Siluanov on Tuesday said Russia may cut its planned borrowing this year due to better-than-expected budget revenues and could be able to keep the state’s debt to gross domestic product ratio at no more than 20% over three years. Russian stock indexes were higher. The dollar-denominated RTS index was up 2.3% at 1,481.2. The rouble-based MOEX Russian index grew by 1.9% to 3,478.8. For Russian equities guide see For Russian treasury bonds see