The U.S. government is considering slapping tariffs of up to 25 percent on imported cars, a move which could hit South Korea hard, as automobiles are one of its key export items to the U.S.

In a statement issued on Wednesday, U.S. President Donald Trump said he had instructed Commerce Secretary Wilbur Ross to launch an investigation into imports of cars, trucks and auto parts through Section 232 of the Trade Expansion Act “to determine their effects on America’s national security.”

The Wall Street Journal on Wednesday quoted sources familiar with the issue as saying that Trump is seeking new tariffs of as much as 25 percent on automobile imports.

Currently, the U.S. applies tariffs of two-and-a-half percent on imported automobiles, such as sedans, and tariffs of 25 percent on imported pickup trucks.