Wall Street stocks opened lower on Tuesday as investors fretted about a possible U.S. government credit downgrade and concerns grew about the economy's growth prospects.

The Dow Jones industrial average dropped 49.19 points, or 0.41 percent, to 12,083.30. The Standard & Poor's 500 Index fell 7.23 points, or 0.56 percent, to 1,279.71. The Nasdaq Composite Index lost 16.46 points, or 0.60 percent, to 2,728.15.

(Reporting by Chuck Mikolajczak)