Equities briefly pared their losses after the Federal Reserve said it would continue its policies of stimulating the economy, though the decision was expected, and shares subsequently slid back.
About 70 per cent of stocks traded on the New York Stock Exchange closed lower while three-fourths of Nasdaq-listed shares ended in negative territory.
The Fed said recent budget tightening in Washington could be a risk to growth, even as it noted some improvement in the labor market.
Materials and energy stocks led declines as expectations of slower growth pushed basic materials prices lower. An index of commodities fell 1.7 percent while the S&P energy index slid 1.6 percent and the S&P materials index lost 1.8 percent. Copper prices fell 3.6 percent, the most in a day since early April 2012.
Exxon Mobil fell 1.7 percent to $87.51 while US shares of mining giant Rio Tinto shed 2.7 percent to $44.82.
The S&P 500 has recently ended sessions much stronger than its early lows as traders bought equities on signs of weakness.
The Dow Jones industrial average lost 138.85 points, or 0.94 per cent, to 14,700.95 at the close. The Standard & Poor’s 500 Index dropped 14.87 points, or 0.93 per cent, to finish at 1,582.70. The Nasdaq Composite Index slid 29.66 points, or 0.89 per cent, to close at 3,299.13.
Both MasterCard dropped 2.4 percent to $539.82. Merck fell 2.8 per cent to $45.69 and weighed on the Dow. Visa Inc, a competitor of MasterCard, fell 1.5 per cent to $166.02.