La Malbaie, Quebec: Bruising for a fight, President Donald Trump barreled into the Group of Seven summit Friday, confronting longtime US allies over a burgeoning trade dispute and insisting Russia should be brought back into the fold.

Trump joined the leaders of major industrialised nations in an idyllic Canadian resort town after days of escalating conflict over new US tariffs he slapped on imports of steel and aluminum. Facing pointed criticism from increasingly disillusioned allies, he punched back, uncowed by the growing global outcry.

"Look, all of these countries have been taking advantage of the United States on trade," Trump told reporters as he left the White House, repeating his longstanding complaints about trade deficits and tariffs. He declared, "We have to straighten it out."

However, Trump did seek to lower the temperature after his arrival. He bantered easily with Canadian Prime Minister Justin Trudeau, joking that the neighbouring leader had "agreed to cut all tariffs and all trade barriers." And he emphasised a "good relationship" with French President Emmanuel Macron, saying they sometimes have a "little test" on trade, but predicting a positive outcome.

Still, the fundamental differences remained clear. Trump again railed against trade deficits with other countries and repeated that he may pursue separate negotiations with Canada and Mexico to replace the North American Free Trade Agreement.