U.S. stocks dropped on Monday as growing concerns about heavy debt loads both domestically and abroad added more uncertainty to a volatile market.

The Dow Jones industrial average <.DJI> dropped 128.29 points, or 1.09 percent, to 11,667.87. The Standard & Poor's 500 Index <.SPX><.INX> lost 15.31 points, or 1.26 percent, to 1,200.34. The Nasdaq Composite Index <.IXIC> fell 33.33 points, or 1.30 percent, to 2,539.17.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)