G7 says to fight protectionism, cut barriers after summit

G7 leaders issued a joint pledge today to combat protectionism and cut trade barriers as they wrapped up a fractious summit in Canada soured by a row over the US imposition of tariffs on its allies.

After two days of often fierce arguments between the United States and both the summit hosts and Europe, the organisation issued a joint statement which attempted to paper over their cracks.

But the attempts to convey at least a semblance of unity were undermined when Canada's Prime Minister Justin Trudeau confirmed he was going ahead with his tariffs against the US in response to US moves against his country's steel and aluminium industries.

The eight-page statement also included joint commitments to ensure that Iran will "never seek, develop or acquire a nuclear weapon" as well as demands for Russia to stop undermining Western democracies.

There was also an agreement to disagree on climate change in the wake of Trump's decision to leave the Paris climate accord last year which further underlined the divide between the Group of Seven's powerhouse and its six co-members.

During the summit, Trump was accused of seeking to undermine the "rules-based" international order but the final statement began by stressing "the crucial role of a rules-based international trading system" as well as a commitment to "continue to fight protectionism."

But in an apparent nod to Trump, it also pledged to push for swift reforms to the World Trade Organisation which the US president has said has been a "disaster" for his country.

"We commit to modernise the WTO to make it more fair as soon as possible. We strive to reduce tariff barriers, non-tariff barriers and subsidies." Speaking at a post-summit press conference, Trudeau acknowledged that there were major differences with Trump.

"What we did this weekend was come together, roll up our sleeves and figure out a consensus language that we could all agree to," Trudeau said in the town of La Malbaie where leaders have been meeting since Friday morning.

"Obviously the president will continue to say what he says." Trudeau again denounced Trump's decision to invoke national security concerns to impose tariffs on aluminium and steel as "insulting" to the Canadian war veterans who had fought alongside US allies.

And he said he told Trump "it would be with regret but it would be with absolute clarity and firmness that we move forward with retaliatory measures on July 1, applying equivalent tariffs to the ones that the Americans have unjustly applied to us."

Trump left the summit early headed for his meeting with the leader of North Korea on Tuesday.

But in a tweet after flying out of Canada, the US president showed he was in no mood to back down in any trade dispute.

"The United States will not allow other countries to impose massive Tariffs and Trade Barriers on its farmers, workers and companies. While sending their product into our country tax free," he said.

"We have put up with Trade Abuse for many decades - and that is long enough."