(Reuters) -President Donald Trump's administration is preparing a new probe into drug pricing practices among U.S. trading partners, a move that would lay the ground for fresh tariffs, the Financial Times reported on Wednesday, citing sources familiar with the matter. 

Reuters could not immediately verify the report. 

The imminent investigation would consider whether U.S. trading partners are underpaying for drugs, the report said, adding that the investigation would come under Section 301 of the Trade Act of 1974.

The White House did not immediately respond to a Reuters' request for comment. 

U.S. patients currently pay by far the most for prescription medicines, often nearly three times more than in other developed nations.

In late September, Trump said the U.S. would impose a 100% tariff on imports of branded or patented pharmaceutical products, unless a pharmaceutical company is building a manufacturing plant in the United States. 

Trump has not followed through on the threat as he presses pharmaceutical companies to lower U.S. drug prices.

Earlier this year, Trump sent letters to the leaders of 17 major pharmaceutical companies outlining how they should slash U.S. prescription drug prices to match those paid abroad.