A World Trade Organisation court on Tuesday reaffirmed a ruling against the US for the way it calculates emergency tariffs on imports it deems unfairly priced, the latest stage in a long-running case brought by Japan.

The ruling by the WTO’s appellate body opens the way for Japan to seek up to $250m (€177m, £151m) in trade sanctions on the US, and is likely to stoke a dispute about the use of so-called “antidumping” measures against imports by the US. In a separate action, Washington is pushing for the $250m figure to be reduced.