U.S. President Donald Trump’s senior counselor for trade and manufacturing, Peter Navarro, has grouped South Korea with other countries he described as “foreign trade cheaters” as he vowed to correct unfair market conditions in the U.S.

According to the New York Times, Navarro told reporters on Wednesday that “foreign trade cheaters have turned America into a lower-wage assembly operation for foreign parts,” adding that the situation threatens his country’s national security by eroding its defense and manufacturing bases.

Navarro said South Korea, Japan and Germany have undermined the ability of U.S. companies to sell their cars abroad, calling the situation unfair and saying it’s going to change.

Navarro’s comments came shortly after Trump signed an executive order imposing his long-promised 25 percent tariffs on all cars and light-duty trucks imported into the U.S.

Last year South Korea’s auto exports to the U.S. totaled some 34 billion U.S. dollars, accounting for nearly half the country’s global auto exports.