Stocks in the U.S. fell as comments from Federal Reserve officials reinforced the view that interest rates will rise this year, even as concerns that a global economic slowdown may spread rekindled a selloff in commodities.

The Standard & Poor's 500 Index tumbled through its average price for the past 200 days as resource producers retreated. Copper fell to the lowest level since 2009 and oil slid through $42 a barrel as the Bloomberg Commodity Index sank to the lowest since 1999. European equities slid as the outlook for earnings worsened even as Mario Draghi hinted at adding stimulus.

Divergent signals on monetary policy continued to dominate financial markets, as Fed officials reiterated the case for higher interest rates at their December policy meeting. The European Central Bank president's comments boosted bonds and weakened the euro. A mixed picture on China's economy did little to alleviate concern that demand for resources would continue to wane.

U.S. equities accelerated losses after normally dovish New York Fed President William Dudley said the central bank may need to begin tightening. Fed President James Bullard of St. Louis earlier urged raising target rates, while Chicago Fed leader Charles Evans stressed any increases should be "gradual." Draghi said in Brussels that downside economic risks are "clearly visible" and policy makers will reexamine the degree of accommodation in December.

The S&P 500 dropped 1 percent at 3:18 p.m. in New York, sliding below its 200-day moving average for the first time in two weeks. The gauge has advanced just once in the seven sessions since Yellen reminded investors that December's meeting could bring the first rate increase in six years. The index has failed to hold gains after rising within 1 percent of its all-time high on Nov. 3.