President Donald Trump late Thursday threatened a 35% tariff on goods imported from Canada, a dramatic escalation in an on-again, off-again trade war with America’s northern neighbor and one of its most important trading partners.

The US will impose a tariff of 35 per cent on Canadian goods from August 1, Donald Trump said in a letter late on Thursday. The US president separately told NBC News on Thursday that any countries that had not received a letter from him setting out new tariff regimes would face so-called blanket tariffs of 15-20 per cent.