The Trump administration is proceeding with probes into imports of pharmaceuticals and semiconductors as part of a bid to impose tariffs on both sectors on grounds that extensive reliance on foreign production of medicine and chips is a national security threat, Federal Register filings on Monday showed. The filings announce 21-day public comment periods and mark President Donald Trump's latest use of Section 232 of the Trade Expansion Act of 1962 as justification for so-called sectoral tariffs aimed at boosting domestic production of goods he says are critical to national security.