Wall St tumbles as Ukraine tensions rise, China slows
Selling accelerated in afternoon trading after Russia launched military exercises near its border with Ukraine, showing no sign of backing down in its plans to annex its neighbor's Crimea region despite a stronger-than-expected push for sanctions from the EU and the United States.
In an unusually robust and emotionally worded speech, German Chancellor Angela Merkel warned of "catastrophe" unless Russia changes course.
The S&P 500 broke below its 10-day and 14-day moving averages, which were acting as short-term technical support levels. It also broke below the 1,850 level.
The Dow Jones industrial average fell 231.19 points or 1.41 percent, to 16,108.89, the S&P 500 lost 21.86 points or 1.17 percent, to 1,846.34 and the Nasdaq Composite dropped 62.912 points or 1.46 percent, to 4,260.42.
European stocks hit a five-week closing low as worries over economic growth in China and tension in Ukraine took their toll on market sentiment.
A broad sell-off among UK retailers, after a profit warning by supermarket Morrison's, also contributed to the downward momentum.
The FTSEurofirst 300 index of top European shares closed down 1.1 percent at 1,293.35 points, its lowest close since February 6. The index has slipped more than 4 percent since late February.