Stocks fell on Thursday after the president of the European Central Bank expressed caution over more bond purchases to ease the region's debt crisis.

The Dow Jones industrial average <.DJI> was down 45.41 points, or 0.37 percent, at 12,150.96. The Standard & Poor's 500 Index <.SPX> dropped 8.86 points, or 0.70 percent, at 1,252.15. The Nasdaq Composite Index <.IXIC> fell 19.27 points, or 0.73 percent, at 2,629.94.

(Reporting by Angela Moon; editing by Jeffrey Benkoe)