Washington, July 21 -- US President Donald Trump has signed a proclamation under Section 232 of the Trade Expansion Act of 1962 to adjust aluminium imports, citing national security concerns and seeking to boost investment in the domestic aluminium industry, according to a White House statement.

The fact sheet said tariffs on imported aluminium were aimed at protecting the country's defence and defence-related industrial base.

It said, "aluminium is a key input for the production of US military systems, including armoured vehicles, naval vessels, spacecraft, and missiles, as well as other key strategic products."

These systems and their components rely on high-strength advanced aluminium alloys that can only be produced using primary a...