Donald Trump has pledged to use his executive power to lower the price of prescription drugs in the United States to make them more aligned with other countries.

The U.S. president said he would sign an order on Monday that would lower prescription drugs and medicine prices "almost immediately" "30% to 80%.

Trump wrote on Sunday's social media platform that his social media platform said, "It's hard to explain, it's very embarrassing" why the U.S. drug prices are higher than many other countries.

"Pharma/pharmaceutical companies will say that for years it was R&D costs, all of which are, and, anyway, will be, and, anyway, will be borne by the "sucker" of the United States."

He added that he will introduce the "most popular country" policy, where the United States is priced the same as the lowest in the world".

The comments sparked a sell-off in the drug on Monday because they could fall if prices in the U.S. had to be lowered.

In London, shares of pharmaceutical companies Astrazeneca and GSK fell as much as 5% and 2.6% in early trading, respectively. Shares of Novo Nordisk, which is listed in Frankfurt, fell 7.5%, while Swiss group Roche Holdings fell 3.6%.

In South Korea, shares of SK Biopharmaceuticals and Samsung Biopharmaceuticals fell 2.7% and 4.7% respectively. In Hong Kong, Bergean fell 8.9%, and innovative biologics fell 7%.

Trump targeted high drug costs during his first administration, which aimed to raise salaries on certain medicines under Medicare’s leadership. But it was striked in federal court after the drug company's challenge.

Under President Joe Biden's inflation reduction bill, the U.S. government has indeed negotiated the prices of some of the most expensive drugs used in the federal health insurance plan. Medicare covers 66 million Americans, most of whom are 65 years old or older.

However, Trump did not specify on Sunday whether its executive order applies to Medicare, Medicaid or other government health plans.

He suggested that industry lobbyists were unsuccessful at the White House, although big pharmaceutical companies and industry agencies have already donated to his inauguration.

"President donations can do miracles, but not with me, not with the Republican Party. We will do the right thing, Democrats have fought for many years," he said.