WASHINGTON, DC, United States (AFP) — President Donald Trump delayed the start of tariffs on Mexico and Canada for a month Monday after the US neighbours struck last-minute deals to tighten border measures against the flow of migrants and the drug fentanyl.

Global stock markets had slumped as Trump’s threat of sweeping 25 per cent levies on exports from Canada and Mexico to the United States sparked fears of a global trade war.

But after calls with Trump just hours before the US tariffs were due to take effect, both Canadian Prime Minister Justin Trudeau and Mexican President Claudia Sheinbaum struck deals for a postponement.

Trump said that after “very friendly” talks with Sheinbaum he’d “immediately pause” the tariffs on Mexico, and that his counterpart had agreed to send 10,000 troops to the US-Mexico frontier.

Tensions appeared higher between the US and Canada, but afer two separate calls Trump later said he was “very pleased” and was announcing a 30-day halt in the tariffs.

“Canada has agreed to ensure we have a secure northern border, and to finally end the deadly scourge of drugs like fentanyl that have been pouring into our country,” he said.

Talks on final deals would continue with both countries, he added.

Trudeau said after the “good call” that Canada deploy nearly 10,000 frontline officers to help secure the border, list drug cartels as terrorists, appoint a “fentanyl czar” and crack down on money laundering.

It was not clear the real extent of the changes on the Canadian border, given that just this December authorities there said they already had 8,500 personnel deployed.

China remains in the firing line for Trump tariffs. It faces a further 10 per cent duty on top of existing levies.

The US president said last-minute talks between Washington and Beijing will likely be held “probably in the next 24 hours” to avoid new tariffs on Chinese imports.

Canada, China, and Mexico are the United States’s three biggest trading partners, and Trump’s threatened tariffs have sent shock waves through the global economy.

The White House said earlier there had been a “heck of a lot of talks” over the weekend.

“This is not a trade war, this is a drug war,” National Economic Council Director Kevin Hassett told CNBC, complaining that “the Canadians appeared to have misunderstood the plain language”.

However, US Government figures show that only a minimal quantity of drugs comes via Canada.

Canada had vowed to respond strongly to the tariffs.