US stocks veered off course on Wednesday after the White House said President Donald Trump would announce fresh tariffs on the auto sector after markets close.

The Dow Jones Industrial Average closed down 0.3 percent at 42,454.79, while the broad-based S&P 500 Index fell 1.1 percent to 5,712.20.

The tech-focused Nasdaq Composite Index tumbled 2.0 percent to 17,899.01, while the CBOE Volatility Index -- Wall Street's so-called "fear gauge" -- jumped seven percent, reflecting market jitters.

The turn in market sentiment followed White House Press Secretary Karoline Leavitt's remarks earlier Wednesday that Trump would unveil the "auto industry" tariffs at 4:00 pm (2000 GMT).

"It's the continuation of worries regarding the tariffs and the impact on the economy," Peter Cardillo from Spartan Capital Securities told AFP.

"Everyone is (also) waiting to see what the reciprocal tariffs are going to be on April the 2nd," he added. "So it's a continuation of this wall of worries."

US automakers fell on the news, with Tesla closing down 5.6 percent.

General Motors shed 3.1 percent, while Ford initially slipped, before reversing course to finish up 0.1 percent. (AFP)