Stocks fell sharply on Friday as worries of a trade war between the U.S. and China grew. Wall Street also digested employment data that missed analyst expectations. The Dow Jones industrial average fell 613 points, with Boeing and Caterpillar as the biggest decliners in the index. The S&P 500 declined 2.2 percent, with industrials as the worst-performing sector. The Nasdaq composite dropped 2.1 percent.