European markets slumped, dragging U.S. stocks down along with them, after Greece said it will miss deficit reduction targets it agreed to as part of its bailout deal. Benchmark indexes in Germany, France and Spain all fell 2 percent.
The Dow briefly turned higher after 10 a.m., when the Institute of Supply Management said its gauge of U.S. manufacturing did better than Wall Street had predicted in September. The Dow and S&P turned mixed within 20 minutes, then took a sharp slide shortly after noon.
The Dow Jones industrial average was down 186 points, or 1.7 percent, to 10,729 at 1:15 p.m. Eastern.
The S&P 500 lost 22, or 2 percent, to 1,109. That's below its closing low of 1,119 for the year, reached on Aug. 8.
The Nasdaq composite fell 52, or 2.2 percent, to 2,362.
All 10 company groups in the S&P index fell. Banks, energy, and consumer discretionary stocks had the steepest declines. The yield on the 10-year Treasury note fell to 1.79 percent from 1.91 percent late Friday as investors piled into lower-risk investments.
"The market is continuing to trade based on what is happening in Europe, and that is going to overshadow everything else," said Quincy Krosby, market strategist at Prudential Financial. "The math (for the Greek bailout) didn't add up a year ago, and the math doesn't add up today. The market knows that and is waiting for the Europeans to acknowledge it."
The renewed concerns about Europe's debt problems pushed the U.S. dollar up 0.8 percent against the euro. That could hurt large U.S. companies that rely on exports by making their products more expensive overseas. Coca-Cola Co. fell 3 percent. Caterpillar Inc., which sells construction equipment globally, lost 3.8 percent.
Concerns that the U.S. economy is headed for another recession helped send the S&P 500 index, the basis for most mutual funds that invest in U.S. stocks, down 14 percent over the three months that ended in September. It was the worst quarter for the stock market since the financial crisis of 2008.
In corporate news, Yahoo gained 2.3 percent to $13.45, after the head of Chinese Internet company Alibaba Group Holdings said he would be interested in buying the company. Yahoo, which recently ousted Carol Bartz as its CEO, has been trying to decide whether to sell parts of the company.
Bank of America fell to its lowest price since the financial crisis in 2008. The bank lost 4.8 percent to $5.83. The company has fallen 56 percent since January.
Netflix rose 0.2 percent after an analyst from Morgan Stanley upgraded the company following a sharp drop in its stock price. Netflix has plummeted 60 percent from its recent high of $304 because of a drop in subscribers and a plan to split its streaming service from its DVD-by-mail business.