¡¡ WASHINGTON, April 6 (Xinhuanet) --US Federal Reserve (Fed) Chairman Alan Greenspan on Wednesday urged the Congress to limit the size of Fannie Mae and Freddie Mac, two biggest mortgage giants in the United States.

    "Without restrictions on the size of (their) balance sheets, weput at risk our ability to preserve safe and sound financial markets in the United States, a key ingredient of support for homeownership," Greenspan said in prepared remarks to the Senate Banking Committee.

    "World class regulation, by itself, may not be sufficient," Greenspan said.

    Fannie Mae is the No. 1 US buyer of home mortgages and Freddie Mac ranks as the second largest buyer in the country. They were created by the US Congress to pump money into the home-mortgage market which has swelled to an 8 trillion dollars now.

    At the end of 1990, Fannie's and Freddie's combined portfolios amounted to 132 billion dollars, or 5.6 percent of the US single-family home mortgage market, Greenspan said. By 2003, those combined portfolios had grown tenfold, to 1.38 trillion dollars or23 percent of the single-family home-mortgage market.

    Greenspan's remarks about the two US mortgage giants repeated awarning that he has been issuing for more than a year: that the country's financial system could be put at risk unless the growth of the two giant mortgage lenders is restrained.

    The Fed chairman's warning also came at a times when the two companies are being accused of accounting problems. Enditem