Stocks fell at the open on Thursday as persistent fears Greece's debt crisis could spread through Europe curbed risk appetite.

An unexpected rise in new claims for unemployment benefits threw cold water on optimism about the state of the labor market, and further hurt sentiment.

The Dow Jones industrial average <.DJI> dropped 43.99 points, or 0.40 percent, to 10,853.53. The Standard & Poor's 500 Index <.SPX> fell 5.73 points, or 0.48 percent, to 1,176.72. The Nasdaq Composite Index <.IXIC> lost 10.52 points, or 0.43 percent, to 2,420.64.

(Editing by Jeffrey Benkoe)