Stocks ended sharply lower on Thursday as mounting sovereign debt problems in Europe and an unexpected rise in jobless claims put investors on the defensive just ahead of the crucial payrolls report.

Based on the latest available data, the Dow Jones industrial average <.DJI> fell 268.37 points, or 2.61 percent, to end unofficially at 10,002.18. The Dow industrials briefly fell below 10,000 in the final minutes of trading.

The Standard & Poor's 500 Index <.SPX> slid 34.17 points, or 3.11 percent, to close unofficially at 1,063.11. The Nasdaq Composite Index <.IXIC> lost 65.48 points, or 2.99 percent, to finish unofficially at 2,125.43.

(Reporting by Caroline Valetkevitch; Editing by Jan Pachal)