Stocks tumbled on Tuesday after investors were blindsided by a surprise call for a Greek referendum on a EU bailout plan, casting doubt on the sustainability of the recent market rally.

The Dow Jones industrial average was down 295.39 points, or 2.47 percent, at 11,659.62, according to the latest available figures. The Standard & Poor's 500 Index was down 34.96 points, or 2.79 percent, at 1,218.34. The Nasdaq Composite Index was down 77.45 points, or 2.89 percent, at 2,606.96.

(Reporting by Ryan Vlastelica; Editing by Kenneth Barry)