US President Donald Trump on Thursday moved the Supreme Court to challenge a federal court’s ruling that said the President is not authorised to impose sweeping tariffs on foreign imports.

In the appeal filed with the top court, Trump defended the tariffs imposed on India and argued that they were a crucial part of his efforts to pause the ongoing Russia-Ukraine war.

"The President recently authorised International Emergency Economic Powers Act (IEEPA) tariffs against India for purchasing Russian energy products, to deal with a preexisting national emergency regarding Russia’s war in Ukraine, as a crucial aspect of his push for peace in that war-torn country," it said.

"The Federal Circuit did not question that those crises constitute 'unusual and extraordinary threat[s]” to “national security, foreign policy, or [the US] economy” sufficient to trigger the President’s emergency powers under IEEPA. 50 USC 1701(a)," it added.

The appeal also said that "decision casts a pall of uncertainty upon ongoing foreign negotiations that the President has been pursuing through tariffs over the past five months, jeopardising both already negotiated framework deals and ongoing negotiations."

This came as Trump warned that the US might have to "unwind" trade agreements with the European Union, Japan and South Korea, among others, if it loses the case, saying that such a setback would cause the country "to suffer so greatly."

"We made a deal with the European Union where they're paying us almost a trillion dollars. And you know what? They're happy. It's done. These deals are all done," he said. "I guess we'd have to unwind them."

"Our country has a chance to be unbelievably rich again. It could also be unbelievably poor again. If we don't win that case, our country is going to suffer so greatly, so greatly," he added.

Jeffrey Schwab, an attorney with the Liberty Justice Centre who represents small businesses affected by the tariffs, said the impact is also severe for his clients.

"These unlawful tariffs are inflicting serious harm on small businesses and jeopardising their survival. We hope for a prompt resolution of this case for our clients," he said.

The ruling by the US Court of Appeals for the Federal Circuit in Washington DC, applied to two sets of tariffs, one being Trump’s “reciprocal” duties announced in April as part of his trade measures and another set in February against China, Canada and Mexico. It does not affect other tariffs imposed under different statutes, including those on steel and aluminium imports.

In a 7-4 judgement, the court observed, "The statute bestows significant authority on the President to undertake a number of actions in response to a declared national emergency, but none of these actions explicitly include the power to impose tariffs, duties, or the like, or the power to tax," according to Reuters.

The court further said Trump had exceeded his authority under the International Emergency Economic Powers Act.