The Dow Jones industrial average lost 29.07 points to close at 6499.34, giving the red-hot blue-chip barometer its first two-day losing streak in more than a month.
Advancers led decliners by a 7-to-6 margin on the New York Stock Exchange, with 1,337 up, 1,136 down and 851 unchanged. NYSE volume was 377.11 million shares vs. 533.46 million yesterday.
Broad-market indexes were mixed. The Standard & Poor's 500-stock index fell 0.97 to 754.99, and the NYSE's composite index fell 0.50 to 397.48.
But the American Stock Exchange's index rose 0.31 to 588.64. And the technology-rich Nasdaq composite index rose 6.12 to 1,287.32, a record high for the third straight session as bellwether computer-related shares bucked the day's downward trend.
Oil shares were among the Dow's biggest decliners amid worries that the potential return of Iraqi oil to the world supply will hurt prices.
Stocks started the session lower as the bond market slipped from an early rally that had pulled interest rates back down toward their lowest level since early March. The yield on the 30-year Treasury bond - a key determinant of corporate and consumer borrowing costs - fell from late yesterday's 6.44 percent to nearly 6.38 percent before rising to 6.42 percent.