NEW YORK: Wall Street stocks tumbled at midday Monday on worries about trade conflicts and the prospects for the tech sector as several prominent highflyers came under pressure. Stocks opened the week lower and losses quickly accelerated as the session progressed. Near 1630 GMT, the tech-rich Nasdaq Composite Index was down 2.5 percent at 6,889.62. The Dow Jones Industrial Average shed 2.0 percent to 23,616.68, while the broad-based S&P 500 fell 2.2 percent to 2,582.40. Investors pounded several leading tech companies that have faced controversy of one sort or another. These included Amazon, which slumped 4.6 percent as President Donald Trump sharpened attacks on the retailer and its chief, Jeff Bezos, who also owns The Washington Post; Tesla Motors, which dropped 2.4 percent ahead of electric car production figures that analysts expect will miss targets; and Facebook, which shed 2.3 percent as it reels from a scandal over consumer data. Other tech companies with big declines included Google parent Alphabet, down 2.7 percent, Microsoft, down 2.8 percent and Netflix, down 4.4 percent. Worries about a trade war also returned to the forefront after China slapped tariffs on 128 US exports. In addition to that move, which Beijing had telegraphed in retaliation for US tariffs targeting China, Trump again threatened to spike the North American Free Trade Agreement. He said on Twitter that Mexico was doing too little to counter illegal immigration into the United States. The development weighed on several export-oriented companies, including Boeing, which lost 1.9 percent, Caterpillar, which fell 3.1 percent and General Motors, which shed 1.7 percent. One bright spot was Humana, which rose 4.6 percent on reports it is in talks to be acquired by Walmart. Walmart fell 3.8 percent. This week’s calendar features a number of key data releases, including the March US jobs report and auto sales for the same period.