Aug 23 (Reuters) - U.S. stocks were lower at the open on Wednesday after President Donald Trump warned of a government shutdown to build a Mexico border wall and threatened to terminate a trade agreement with Mexico and Canada.
The Dow Jones Industrial Average fell 74.12 points, or 0.34 percent, to 21,825.77. The S&P 500 lost 10.87 points, or 0.44 percent, to 2,441.64. The Nasdaq Composite dropped 34.04 points, or 0.54 percent, to 6,263.44. (Reporting by Tanya Agrawal; Editing by Savio D'Souza)