(BSS/AFP) - President Donald Trump signed an order Monday allowing officials to offer lower aluminum tariff rates for firms that commit to help set up smelters in the United States.

The US tariff on aluminum imports generally stands at 50 percent but under the new plan, firms can qualify for half the tariff rate.

Trump`s latest order directs the US commerce secretary to set up an incentive program for businesses that "will invest in building, expanding, or refurbishing aluminum smelters" in the country, said the White House.

The program calls for companies to submit business plans.

If approved, firms can import "a commensurate level of primary aluminum" at half the applicable tariff rate, the White House added in its fact sheet.

The White House noted that aluminum is critical for the production of US military systems like armored vehicles and naval vessels, alongside missiles.

Since returning to power last year, Trump has imposed sweeping tariffs on imports from US trading partners.

While many of these tariffs were struck down by the Supreme Court in February, the US leader`s sector-specific duties targeting industries like steel, aluminum and automobiles remain intact.

But Trump has also adjusted his metals tariffs in past months as firms grapple with onerous systems of compliance.