MOSCOW, March 22 (Reuters) - The Russian rouble weakened on Monday to a more than two-week low versus the dollar, as new sanctions against Moscow loomed and with emerging market currencies struggling after the abrupt firing of Turkey’s central bank chief sent the lira tumbling. At 0741 GMT, the rouble was 0.7% weaker against the dollar at 74.63, its weakest mark since March 5. It had lost 0.5% to trade at 88.69 versus the euro . The lira slid 15% to a near 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, before clawing back some overnight losses. 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. 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. The Russian currency should gain support this week from a month-end tax payments period that usually leads export-focused companies to convert foreign currency revenues to meet local liabilities. Last week’s surprise 25 basis point rate hike by the central bank should lend the rouble additional support. Brent crude oil, a global benchmark for Russia’s main export, was down 1.2% at $63.75 a barrel. Russian stock indexes were mixed. The dollar-denominated RTS index was down 0.4% to 1,468.5. The rouble-based MOEX Russian index was 0.1% higher at 3,478.2. For Russian equities guide see For Russian treasury bonds see