President Donald Trump’s administration pressed forward with plans to impose tariffs on semiconductor and pharmaceutical imports by initiating trade probes led by the Commerce Department.

The moves, announced Monday in the Federal Register, are a precursor to imposing tariffs and threaten to broaden the president’s sweeping U.S. trade war.

The Commerce Department said it had begun investigating the impact on U.S. national security of "imports of semiconductors and semiconductor manufacturing equipment” as well as "pharmaceuticals and pharmaceutical ingredients, including finished drug products” in a pair of register notices.