The looming legal fight injects uncertainty into President Donald Trump's evolving tariffs plan, which has upended the global economy since April 2.

One official said that the president is unlikely to delay his initial 90-day pause on some of his highest rates.

The president's plan - where countries face between 11% to more than 100% tariffs on goods brought into the US - was announced in April. But the majority of the tariffs were paused by Trump for 90 days in the wake of stock market volatility.