Donald Trump announced on Saturday that he would raise a temporary tariff rate on US imports from all countries from 10% to 15%, less than 24 hours after the US supreme court ruled against the legality of his flagship trade policy.

Infuriated by the high court’s ruling on Friday that he had exceeded his authority and should have gotten congressional approval for the tariffs, the US president railed against the justices who blocked his use of tariffs, calling them a “disgrace to the nation”, and ordered an immediate 10% tariff on all imports, in addition to any existing levies.

In a post on Truth Social on Saturday announcing the further increase, Trump wrote: “I, as President of the United States of America, will be, effective immediately, raising the 10% Worldwide Tariff on Countries, many of which have been ‘ripping’ the U.S. off for decades, without retribution (until I came along!), to the fully allowed, and legally tested, 15% level.”

The law according to section 122 of the Trade Act of 1974 allows the president to impose a levy of up to 15% for 150 days, although it could face legal challenges. During that period, his administration will work on issuing new and “legally permissible” tariffs, Trump said.

The president also attacked the supreme court’s 6-3 ruling as “ridiculous, poorly written, and extraordinarily anti-American” in his Truth Social post.

In remarks at the White House on Friday, Trump told reporters: “It’s my opinion that the court has been swayed by foreign interests and a political movement that is far smaller than people would ever think.” He added: “I’m ashamed of certain members of the court. Absolutely ashamed for not having the courage to do what’s right for our country.”

He praised the three justices who dissented in the opinion: Brett Kavanaugh, who wrote the main dissent, Clarence Thomas and Samuel Alito. The others – including two of his appointees, Amy Coney Barrett and Neil Gorsuch – drew his derision.

“They’re just being fools and lapdogs for the Rinos [“Republicans in name only”] and the radical-left Democrats, and not that they should have anything at all to do with it,” Trump said. “They’re very unpatriotic and disloyal to our constitution.”

He called Barrett and Gorsuch “an embarrassment to their families” and said they were “barely” invited to the State of the Union address next week.

Asked for evidence of foreign influence over the supreme court, Trump replied: “You’re going to find out.”