Manufacturing in the United States shrank at its sharpest clip in more than three years last month, a survey showed on Tuesday, the latest sign that the slowing global economy is weighing on an already weak U.S. recovery.

August was the third month in a row of contraction in the factory sector, according to an Institute for Supply Management survey. Firms hired the fewest workers since late 2009, a possible red flag for the August U.S. jobs report due on Friday.