Check back for updates throughout the trading dayU.S. equity futures extended declines in early Tuesday trading, matching downside moves for oil prices and the dollar, as markets reacted to the fast-changing dynamic on tariffs and the potential for a protracted trade war between the world's two biggest economies.

The first round of Chinese sanctions to hit US oil were received with a whimper, and traders are speculating that the move is unlikely to rattle American exports of crude.

China's finance ministry said it would impose levies of 15% for U.S. coal and 10% for crude oil, farm equipment and some cars.