FILE PHOTO: Traders work on the floor of the New York Stock Exchange (NYSE) in New York, U.S., July 6, 2018. REUTERS/Brendan McDermid

TOKYO (Reuters) - U.S. stock futures extended their losses on Wednesday after Washington announced a plan to slap tariffs on an extra $200 billion of imports from China, sharply escalating a trade war between the world’s two biggest economies.

Dow Jones mini futures fell as much as 1 percent while S&P500 e-mini futures, the world’s most liquid futures, were down 0.8 percent.