Stocks extended losses in afternoon trade on Wednesday, with the S&P 500 and the Nasdaq off more than 3 percent as a spike in Italian bond yields heightened fears the debt crisis in Europe was spreading.

The Dow Jones industrial average slid 352.91 points, or 2.90 percent, at 11,817.27. The Standard & Poor's 500 Index dropped 40.35 points, or 3.16 percent, at 1,235.57. The Nasdaq Composite Index was down 88.33 points, or 3.24 percent, at 2,639.16.

(Reporting by Angela Moon; editing by Jeffrey Benkoe)