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.

Asian and European equities were also lower amid an escalation of protectionist rhetoric between the world’s top two economies. Market turbulence in recent weeks has also been caused by a selloff in mega-cap technology stocks, as President Donald Trump has criticized Amazon.com Inc. in a series of tweets and as Facebook Inc.’s user-data crisis continues. The S&P 500 had finished back above its 200-day moving average on Tuesday after the White House said the government isn’t going after Amazon.

POLITICS/ECONOMY:

• San Francisco Fed President John Williams was picked to succeed William Dudley as head of the central bank’s powerful New York branch. Considered a centrist on monetary policy, Williams will take over on June 18.
• St. Louis Fed President James Bullard speaks to a bankers’ group in Little Rock, Arkansas. Cleveland Fed President Loretta Mester addresses Central State University in Ohio on the value of diversity in economics.