U.S. stock futures tank after China imposes tariffs on key exports

U.S. stock futures extended declines in New York as jitters over trade tensions between the U.S. and China further escalated. China said it would levy 25 percent tariffs on imports of 106 U.S. products including soybeans, automobiles, chemicals and aircraft, in response to proposed American duties on its high-tech goods.

Futures on the S&P 500 Index fell as much as 1.7 percent after Beijing said the charges will apply to around $50 billion of U.S. imports, matching the scale of proposed U.S. tariffs announced Tuesday. Contracts on the Dow Jones Industrial Average slipped as much as 2 percent, while those on the Nasdaq 100 Index fell as much as 2.3 percent.