Stocks fell further on Wednesday after Federal Reserve Chairman Ben Bernanke expressed concerns about the U.S. economy, saying it faces unusually uncertain prospects.

The Dow Jones industrial average <.DJI> fell 36.55 points, or 0.36 percent, to 10,193.41. The Standard & Poor's 500 Index <.SPX> lost 5.48 points, or 0.51 percent, to 1,078.00. The Nasdaq Composite Index <.IXIC> dropped 13.67 points, or 0.62 percent, to 2,208.82.

(Reporting by Rodrigo Campos; Editing by Jan Paschal)