President Donald Trump on Wednesday said that the United States may be forced to unwind trade deals with the European Union, Japan and South Korea, among others, if the Supreme Court upholds a recent appeals court ruling that declared many of his tariffs illegal, Reuters reported.

Trump stated that his administration would challenge the ruling in the Supreme Court, expressing confidence that there would be a favourable outcome, but warned that losing the case could cause the US “to suffer so greatly”.

“Our country has a chance to be unbelievably rich again,” he said. “It could also be unbelievably poor again.”

The comments mark the first time that Trump has directly linked the legality of his tariffs to the continued validity of the recent trade agreements Washington negotiated with several countries, Reuters reported.

India and the US are also negotiating a trade deal, which could be finalised by November, Union Commerce Minister Piyush Goyal said on Tuesday.

On August 29, a federal appeals court ruled that Trump had overstepped his authority to impose the so-called reciprocal tariffs under an emergency powers statute.

The tariffs were illegal as only the legislative branch of the government, the Congress, has the power to enforce such sweeping measures, the court said.

However, the judges allowed the tariffs to remain in effect until October 14 to give the Trump administration time to appeal to the Supreme Court. The government made the appeal on Wednesday.

Solicitor General D John Sauer urged the court to accept the appeal by next week, hear arguments in early November and “expedite” its ruling, Politico reported.

Friday’s ruling affects two sets of tariffs the US president has imposed.

The first are the reciprocal tariffs imposed separately for dozens of countries, including India. These range from the baseline 10% for some countries to the 34% rate imposed on China.

Trump’s tariffs had taken effect on April 9. Hours later, however, he reduced the rates on imports from most countries to 10% for 90 days to provide time for trade negotiations. Washington has been negotiating separate trade deals with several trading partners to extract economic concessions.

The US president had repeatedly said he intended to impose a reciprocal tax on several nations citing high tariffs the countries impose on foreign goods.

The tariff plans have led to concerns of a broader trade war that could disrupt the global economy and trigger a recession.

The ruling also affects the 25% levy the US president imposed on select goods imported from Canada, China and Mexico citing what the Trump administration claimed was a failure of those nations to curb the flow of fentanyl.

The ruling does not cover other tariffs imposed by Washington, such as 50% levies on steel and aluminium, under other laws (1974 Trade Act and the 1962 Trade Expansion Act).