Chairman Ben Bernanke offered a sour assessment of the U.S. economy Tuesday and said the Federal Reserve is ready to take further action if growth doesn't pick up. But Bernanke provided no clues about what steps the Fed might take or whether any action was imminent.

Investors were hoping Bernanke would signal that the Fed planned to launch another round of bond purchases, to drive down long-term interest rates and encourage more borrowing and spending.

Stock prices, which had been up moderately in early trading, slipped after Bernanke's testimony was released. As he began testifying to the Senate Banking Committee just after 10 a.m. Eastern time, the Dow Jones industrial average was down about 14 points. Stocks fell further later in the morning.

Bernanke's midyear report to Congress on the economy comes as job growth has slumped, manufacturing has weakened and consumers have cut back on spending.