US stocks extend losses; Dow -2.2%

Wall Street stocks sharply extended losses Thursday morning after Federal Reserve Chair Janet Yellen said it was "premature" to assess the impact of global market turmoil on the US economy. Near 1650 GMT, the Dow Jones Industrial Average was at 15,570.85, down 343.89 points (2.16 percent). The broad-based S&P 500 fell 33.61 (1.81 percent) to 1,818.25, while the tech-rich Nasdaq Composite Index dropped 59.05 (1.38 percent) to 4,224.54.