Stocks traded sharply lower amid worries over global growth in Europe and China, and continuing concerns about debt troubles in peripheral euro zone countries.
The Dow Jones Industrial Average fell more than 160 points after ending a volatile week loweron Friday.
Most blue-chip components sank, led by Caterpillar.
TheS&P 500 fell more than 1 percent, while the tech-heavy Nasdaq sank more than 1.5 percent. The CBOE Volatility Index, widely considered the best gauge of fear in the market, rose above 18.
All key S&P 500 sectors fell, led by industrials,technology and energy.
Troubles in Europe mounted, beginning with Standard & Poor’s downgrade of Italy's outlook to "negative" from "stable" over the weekend. Then Spain's ruling Socialist party suffered an election setback.On Monday, European purchasing managers index dataindicated a slowdown in growth in the euro zone, with German and French numbers below expectations.
Also in Europe, several leaders called for Greece to avoid debt restructuring and push ahead with austerity measures. The focus on Monday remains on whether Greece will receive another handout. Many investors fear that if Greece restructures its debt, Ireland and Portugal could follow suit.
President Barack Obama was in Dublin, Ireland on Monday morningwhere he will talk with the Prime Minister about debt and the country’s economy at the start of a European tour.
And in China, an index of manufacturing growth fell in May, an indication the economy is slowing down.
The news of slowing global growth sent oil prices lower. U.S. light, sweet crude fell more than 3 percent to below $97 a barrel. In London, Brentcrude fell nearly 3 percent to nearly $109.
The euro zone troubles pushed the euro to a two-month lowagainst the dollar. The dollar index rose more than 1 percent against a basket of currencies. Meanwhile, gold stablizedabove $1,513 an ounce, while silver was down slightly, just below $35 an ounce.