WASHINGTON- The Trump administration is seeking to use NAFTA to boost the U.S. steel and other basic materials industries by proposing stricter automotive content rules that require the use of North American-made steel, aluminum, copper and plastic resins.

Three people who were briefed on the matter said that the U.S. rules of origin proposal would put these materials on the North American Free Trade Agreement's auto parts tracing list for the first time.

The list is used to verify the regional content level of vehicles and parts so that they can qualify for tariff-free shipment to all three countries.