Kevin Brosseau, a former member of the Royal Canadian Mounted Police and intelligence adviser to Trudeau, will begin the role immediately.

Trump’s threat to impose import taxes of 25% on all goods from Canada was paused for 30 days in February, after he struck a deal with Trudeau that included new US-Canada border measures.

On Monday, Trump added another threat, saying he planned to add a 25% tax on global steel and aluminium imports to the US from 12 March.

If it goes ahead, that will particularly affect Canada, which supplies the US with more steel and aluminium products than any other country.

All 13 of the leaders of Canadian provinces and territories are in Washington DC on Wednesday meeting US lawmakers to make the case against tariffs.

Ontario Premier Doug Ford told reporters on Wednesday morning: “Make no mistake about it, the president knows we’re here, knows we’re concerned.”

The tariff threats coming from the Trump administration has ignited fears of a trade war with Canada, a close US trade and security ally.

Canada has vowed swift retaliation to Trump’s tariffs.

In a press release announcing the fentanyl tsar, Trudeau said the appointment “will accelerate Canada’s efforts to detect, disrupt, and dismantle the fentanyl trade, in partnership with the United States”.

Less than 1% of fentanyl “intercepted at the US border comes from Canada”, the press release said, but “any amount of fentanyl was too much”.

Canada also said it has added new Black Hawk helicopters, drones and nearly 10,000 frontline personnel working to protect the 8,890km (5,525 mile) boundary.

The effort to battle international organised crime also includes a C$200m ($139m; £113m) investment into a new intelligence directive.

Since returning to the White House last month, Trump has been in one trade standoff with Canada and America’s other neighbour, Mexico.

He agreed on 4 February to delay for 30 days his threat of 25% tariffs on all goods arriving from both countries. The postponement came after his two neighbours vowed action to tackle illegal migration and the flow of drugs to the US.

Canada and Mexico are the top US trade partners, along with China.

Trump moved forward with a 10% tariff on all goods entering the US from China, which as retaliated with countermeasures against US goods.