NEW YORK, Feb. 25 (Xinhua) -- U.S. stocks fell further on Wednesday morning after a sharp drop in housing sales exacerbated investors' worries about banks and the housing market.

    U.S. President Barack Obama's speech on Tuesday night did not impress investors much. Obama vowed that the United States would emerge from the economic crisis, promising to use "the full force of the federal government" to shore up the banking system, and suggesting that fixing the credit crisis will cost more than the 700 billion U.S. dollars already committed.

    As part of the Obama administration's Financial Stability Plan, "stress tests" are ready to be taken on the nation's biggest banks to decide if they need further government aid. Banking regulators will be examining Citigroup, Bank of America, JPMorgan Chase and more than a dozen other major financial institutions.

    Sales of existing homes unexpectedly plunged in January to the lowest level in nearly 12 years, adding to the pressure on the market. The National Association of Realtors reported that sales of existing homes fell 5.3 percent to an annual rate of 4.49 million last month, from 4.74 million in December. It was the weakest showing since July 1997.

    The market also focused on Federal Reserve Chairman Ben Bernanke's testimony before Congress on the U.S. economy and monetary policy.

    The Dow Jones fell 110.40, or 1.50 percent, to 7,240.54. Broader indexes also slip. The Standard & Poor's 500 index tumbled 10.41, or 1.35 percent, to 762.73, and the Nasdaq slid 21.42, or 1.49 percent, to 1,420.41.