Trump, who has imposed 25% tariffs on almost all products imported from Canada, has repeatedly said this year that the US has a “$200 billion” trade deficit with Canada – sometimes making the claim explicitly and sometimes using vaguer language about a supposed $200 billion subsidy or loss to Canada.

Finance ministers and central bankers from the G20 top economies gather in South Africa on Wednesday and Thursday, for a meeting marred by the absence or curtailed attendance of key members and disputes over the main issues of climate, debt and inequality.

The Commission's response follows the US imposition of blanket 25% duties on Mexico and Canada and an additional 10% duty on China on Tuesday.