Washington, May 29 (AP) A federal trade court on Wednesday blocked US President Donald Trump from imposing sweeping tariffs on imports under an emergency-powers law.

The ruling from a three-judge panel came after several lawsuits argued that Trump exceeded his authority, left US trade policy dependent on his whims and unleashed economic chaos.

At least seven lawsuits are challenging the levies, the centrepiece of Trump's trade policy.

Tariffs must typically be approved by Congress, but Trump said he has the power to act because the country's trade deficits amount to a national emergency.

He imposed tariffs on most countries of the world at one point, sending markets reeling.

The plaintiffs argued that the 1977 International Emergency Economic Powers Act (IEPPA) does not authorise the use of tariffs.

Even if it did, they said, the trade deficit does not meet the law's requirement that an emergency be triggered only by an "unusual and extraordinary threat".

The US has run a trade deficit with the rest of the world for 49 consecutive years. (AP) ARI

Emergency powers under IEEPA cannot justify unilateral broad tariffs, questioning presidential authority to set trade policy. Whether the President may invoke the International Emergency Economic Powers Act to impose broad import tariffs is contested. Plaintiffs argue the statute does not authorize tariffs and that a longstanding trade deficit does not satisfy the Act's requirement of an unusual and extraordinary threat, raising statutory interpretation and separation of powers concerns over executive authority to set trade policy without congressional approval.