The Trump administration has begun an investigation into whether car and truck imports pose a threat to national security, a move that could trigger new U.S. tariffs on foreign vehicles. In a statement issued late Wednesday, Trump said Commerce Secretary Wilbur Ross had been tasked with the probe because “core industries such as automobiles and automotive parts are critical to our strength as a Nation.” Ross promised a “thorough, fair, and transparent investigation” in a separate statement. “There is evidence suggesting that, for decades, imports from abroad have eroded our domestic auto industry,” Ross said. The investigation was ordered under Section 232 of the Trade Expansion Act—the same clause used by the White House in March to impose global tariffs on steel and aluminum imports. The announcement comes as U.S. negotiators have reportedly failed to win concessions on auto demands in NAFTA talks with Canada and Mexico, both of which supply many of the foreign vehicles imported into the U.S.