World stock markets crumbled for a second straight day on Tuesday, with investors unnerved by prospects for a full-blown global financial crisis despite huge cash injections from central banks. US stocks continued an equities that rout that began in Asia and later spread to European exchanges a day after US investment giant Lehman Brothers stunned the market with a bankruptcy filing. The Federal Reserve on Tuesday pumped an additional $70 billion into the US financial system to help ease credit stresses, a day after upheaval in the American financial system sent shock waves through the stock market, producing the worst day on Wall Street in seven years. Stocks turned higher after a report that the government is considering extending aid to troubled insurer American International Group Inc. A partial recovery in shares of AIG and several other financial companies helped the sector show signs of life after Monday's Dow Jones industrial average lost more than 500 points as investors grappled with the failure of Lehman Brothers, one of Wall Street's most venerable banks, and wondered which domino would be next to fall. The Dow Jones industrial average lost more than 500 points on Monday, more than 4 percent, its steepest point drop since the day the stock market reopened after the Sept. 11, 2001, attacks. The Dow Jones Industrial Average slid 0.54 percent to 10,858.81 in early trade, largely on fears that insurance giant American International Group may be the next credit crunch victim. Shares in AIG plummeted 70 percent at the open. With nervousness gripping exchanges worldwide, the US Federal Reserve, European Central Bank, Bank of England and Bank of Japan together injected $210 billion into the money markets on Tuesday to boost liquidity. London and Tokyo tumbled more than four percent on Tuesday, hitting their lowest levels for more than three years after Wall Street had slumped more than four percent overnight. Russia's main RTS stock market suspended trading after falling by more than 11 percent, a spokeswoman said, following a move by the number two Micex stock market to do the same. Stocks in Oslo plunged by more than eight percent in the wake of the global financial crisis and accentuated by a drop in oil prices. Investors were also awaiting a decision by the US Federal Reserve later in the day that could see a sharp cut in its benchmark interest rate aimed at calming markets. “All eyes will be on the Fed to see if they can ease the financial pressures as they announce their rate decision later. Rumours are rife that we could get up to a 75 basis-point cut in interest rates. “These rumours have snowballed further after lower oil prices eased inflationary pressures,” added Griffiths. On foreign exchange markets, the dollar fell to more than three-month lows against the yen. London's FTSE 100 index of leading shares dived 4.12 percent in afternoon deals, recording the first drop under 5,000 points since June 9, 2005. The share price of British bank HBOS, whose Halifax unit is the biggest mortgage lender in Britain, shed more than 35 percent of its value. The Paris and Frankfurt markets were both down more than three percent while smaller bourses across Europe all suffered badly in the downdraft. Global stocks extended losses Tuesday amid fears of contagion from Lehman, already believed to be pressuring American International Group, one of the world's biggest insurance firms. Rating agencies Standard & Poor's, Moody's and Fitch all lowered AIG's credit ratings and the Wall Street Journal reported Tuesday that the company may have to file for bankruptcy if it cannot secure sufficient fresh funding by Wednesday. Investors were faced with an array of bad news that went well beyond the fall of Lehman, a 158-year-old institution that had survived the market crash of 1929 that heralded the Great Depression. “Lurking close to the surface are mounting pressures on institutions and on any number of investors as the dominoes start to tumble,” said Patrick Bennett, an analyst at Societe Generale. Across Asia on Tuesday, officials called emergency meetings as trading screens went red on the heels of the biggest one-day point loss for Wall Street's Dow Jones index since the September 11 terror attacks. Japanese shares dropped almost five percent and Hong Kong shed 5.4 percent. Seoul shares closed 6.1 percent lower while the South Korean currency, the won, fell 4.3 percent against the dollar, its biggest daily drop in a decade. As markets tumbled, officials appealed for calm – trying to avert a panic after months of market turmoil set off by worries over snowballing defaults on US subprime, or high-risk, housing loans. US Treasury Secretary Henry Paulson vowed on Monday to ensure “stability and orderliness” at home and overseas. Earlier this month Paulson arranged US government guarantees for US mortgage finance giants Freddie Mac and Fannie Mae, and on Monday he reiterated that the US housing mess was “the root” of the current troubles.