U.S. President Donald Trump has signed an executive order to impose 10 percent tariffs on imported goods from all countries, according to a social media post on Friday.

The move came hours after the Supreme Court ruled in a 6-3 vote that his tariff policy under the International Emergency Economic Powers Act (IEEPA) was illegal.

"It is my Great Honor to have just signed, from the Oval Office, a Global 10-percent Tariff on all Countries, which will be effective almost immediately," Trump wrote on Truth Social.

By signing the order, Trump is responding to the Supreme Court's ruling against his tariff policy.

The court ruled that the Trump administration's interpretation of IEEPA would encroach on congressional authority and violate the "'major questions' doctrine," which requires actions of "vast economic and political significance" by the executive branch to be clearly authorized by Congress.

Chief Justice John Roberts delivered the opinion of the court, saying that the president must "point to clear congressional authorization" to justify his extraordinary assertion of the power to impose tariffs.

Justices Clarence Thomas, Samuel Alito and Brett Kavanaugh dissented in the vote.

The ruling did not specify whether tariffs already collected at higher rates would be refunded.

At a press conference on Friday, Trump signaled that he would consider alternative avenues to retain his tariffs.

Trump has already invoked Section 232 of the Trade Expansion Act of 1962 to impose steel and aluminum tariffs for national security reasons.