Emmanuel Macron has called on other members of the G7 to stand up to Donald Trump’s trade policies in the face of what he described as the threat of a new US “hegemony”.

The French president was speaking alongside the Canadian prime minister, Justin Trudeau, who is hosting the G7 summit in Quebec amid sharp disagreements between the U.S. and six other members of G7  industrialized nations over trade, climate change and the nuclear deal with Iran.

Macron called on other G7  leaders not to water down a joint communique at the end of the summit, at the expense of shared values, simply in an effort to win Trump’s signature, warning that a “G6 plus one” outcome was possible.

The challenge brought a tweeted response from Donald Trump, claiming Macron and Trudeau’s governments were pursuing unfair trade practices at the expense of US producers. “Look forward to seeing them tomorrow,” he signed off sardonically. In a second tweet he said Canadian trade policy was "killing our Agriculture".

Donald Trump tweeted:  "Prime Minister Trudeau is being so indignant, bringing up the relationship that the U.S. and Canada had over the many years and all sorts of other things...but he doesn’t bring up the fact that they charge us up to 300% on dairy — hurting our Farmers, killing our Agriculture!"

Trump is due to leave the summit several hours early on Saturday morning, to fly direct to his next engagement, a summit with North Korean leader, Kim Jong-un in Singapore.