Trump has launched numerous national security probes into potential new tariffs on a wide variety of products during his second term, casting a shadow over the global economic outlook and paralysing business decision-making.
Trump also said he would start charging a 50 per cent tariff on bathroom vanities and a 30 per cent tariff on upholstered furniture next week, with all the new duties to take effect from October 1.
The new 100 per cent tariff on any branded or patented pharmaceutical product will apply to all imports unless the company has already broken ground on building a manufacturing plant in the United States, Trump said.
He said the new heavy-duty truck tariffs were to protect manufacturers from "unfair outside competition" and said the move would benefit companies such as Paccar-owned Peterbilt and Kenworth and Daimler Truck-owned Freightliner.
The new tariffs on kitchen, bathroom and some furniture were because of huge levels of imports which were hurting local manufacturers, Trump said.
"The reason for this is the large scale "FLOODING" of these products into the United States by other outside Countries," Trump said on Truth Social.
The Pharmaceutical Research and Manufacturers of America opposed new drug tariffs, saying earlier this year that 53 per cent by value of the $US85.6 billion in ingredients used in medicines consumed in the United States was manufactured in the United States with the remainder from Europe and other US allies.
The US Chamber of Commerce urged the department not to impose new truck tariffs, noting the top five import sources are Mexico, Canada, Japan, Germany, and Finland "all of which are allies or close partners of the United States posing no threat to US national security."
Mexico is the largest exporter of medium- and heavy-duty trucks to the United States. A study released in January said imports of those larger vehicles from Mexico have tripled since 2019.
Higher tariffs on commercial vehicles could put pressure on transportation costs just as Trump has vowed to reduce inflation, especially on consumer goods such as groceries.
Tariffs could also affect Chrysler-parent Stellantis which produces heavy-duty Ram trucks and commercial vans in Mexico. Sweden's Volvo Group is building a $US700 million heavy-truck factory in Monterrey, Mexico, due to start operations in 2026.
Mexico is home to 14 manufacturers and assemblers of buses, trucks, and tractor trucks, and two manufacturers of engines, according to the US International Trade Administration.
The country is also the leading global exporter of tractor trucks, 95 per cent of which are destined for the United States.
"We need our Truckers to be financially healthy and strong, for many reasons, but above all else, for National Security purposes!," Trump added.
Mexico opposed new tariffs, telling the Commerce Department in May that all Mexican trucks exported to the United States have on average 50 per cent US content, including diesel engines.
Last year, the United States imported almost $US128 billion in heavy vehicle parts from Mexico, accounting for approximately 28 per cent of total US imports, Mexico said.
The Japanese Automobile Manufacturers Association also opposed new tariffs, saying Japanese companies have cut exports to the United States as they have boosted US production of medium- and heavy-duty trucks.
