WASHINGTON, United States (AFP) — United States (US) President Donald Trump vowed Friday to impose a 10 per cent tariff on all imports into the United States after the Supreme Court handed him a stinging rebuke by striking down his signature economic policy.

The conservative-majority top court ruled six-three that a 1977 law known as the International Emergency Economic Powers Act (IEEPA) Trump has relied on “does not authorise the president to impose tariffs.”

Trump, who had nominated two of the justices who repudiated him, responded furiously, alleging without any evidence that the court was influenced by foreign interests.

“I’m ashamed of certain members of the court, absolutely ashamed, for not having the courage to do what’s right for our country,” Trump told reporters.

Trump said he would use a separate authority to impose a uniform tariff of 10 per cent — after he spent the past year imposing various rates spontaneously to cajole and punish other countries.

“In order to protect our country, a president can actually charge more tariffs than I was charging in the past,” Trump said, insisting that the ruling left him “more powerful.”