(Updates prices, adds BCS comment) MOSCOW, March 22 (Reuters) - The Russian rouble tumbled towards 75 against the dollar in volatile trade on Monday, touching a more than two-week low as new sanctions against Moscow loomed and Turkey’s nose-diving lira led to a drop in risk appetite. By 1519 GMT, the rouble was 1% weaker against the dollar at 74.88. Earlier, it slumped to 74.9300, its weakest mark since March 4. It had lost 1.2% to trade at 89.30 versus the euro , crossing the 89 threshold for the first time since March 5. Turkey’s lira briefly fell 15% to near its all-time low after President Tayyip Erdogan’s shock weekend ousting of a hawkish central bank governor sparked fears of a reversal of recent rate hikes, putting pressure on riskier assets. The threat of more U.S. sanctions is also hanging over the rouble, with an announcement expected this week. “If U.S. sanctions this week are limited to personal restrictions and additional measures against Nord Stream 2, the rouble could well return to the 73-74/USD range after short-term volatility,” said Dmitry Polevoy, head of investment at Locko Invest. Under tough sanctions, the rouble will most likely weaken to 77-80 versus the dollar, BCS Global Markets said in a note. The rouble has suffered in the past week since U.S. President Joe Biden said his Russian counterpart Vladimir Putin would “pay a price” for alleged meddling in the 2020 U.S. election. Foreign Minister Sergei Lavrov on Monday called for Moscow and Beijing to reduce their dependence on the U.S. dollar and Western payment systems to push back against what he called the West’s ideological agenda. Support for the Russian currency should come this week from a month-end tax payments period that usually leads export-focused companies to convert foreign currency revenues to meet local liabilities. Brent crude oil, a global benchmark for Russia’s main export, erased its earlier losses to trade 0.3% higher at $64.74 a barrel, buttressing Russian stock indexes. The dollar-denominated RTS index was down 0.4% to 1,468.1. The rouble-based MOEX Russian index was 0.4% higher at 3,489.6, supported by the weaker rouble. ($1 = 74.7024 roubles) (Editing by Subhranshu Sahu and Shailesh Kuber)