Stocks fell at open on Friday as an uncertain outcome of Greece's sovereign debt crisis and a mixed report on the U.S. labor market kept investors nervous.

The Dow Jones industrial average was down 70.31 points, or 0.58 percent, at 11,974.16. The Standard & Poor's 500 Index was down 8.28 points, or 0.66 percent, at 1,252.87. The Nasdaq Composite Index was down 15.73 points, or 0.58 percent, at 2,682.24.

(Reporting by Angela Moon; Editing by Padraic Cassidy)