The duties threatened in the letters effectively match the initial reciprocal tariffs Trump briefly imposed on the countries in April.

Trump said on Monday that the US would impose 25 per cent tariffs on Tunisia, Malaysia and Kazakhstan; 30 per cent on South Africa, Bosnia and Herzegovina; 32 per cent on Indonesia; 35 per cent on Serbia and Bangladesh; 36 per cent on Cambodia and Thailand and 40 per cent on Laos and Myanmar.

Donald Trump has warned 14 countries—mostly in Asia—that steep new tariffs will begin August 1 unless fresh trade deals are struck, reigniting tensions with key US partners like Japan, South Korea, and Thailand.