Finance ministers and central bank governors "had a frank exchange on the benefits of an open rules-based trading system and many highlighted the negative impact of unilateral trade actions by the United States", they said in a summary statement written by Canada.
"I don't think our tariffs are anything to do with our friendship and longstanding alliance with Canada", Kudlow said on "Fox News Sunday".
Trans-Atlantic tensions are boiling following yesterday's decision by the United States to impose tariffs on steel and aluminium imports from key allies Canada, Mexico and the European Union. Mexico complained the tariffs will "distort global trade" and said it would penalize US imports including pork, apples, grapes, cheeses and flat steel.
Canadian PM Justin Trudeau on Sunday described United States tariffs as "insulting" to the shared history of the U.S. and Canada as the fallout over Donald Trump's tariff moves continued. But Commerce Secretary Wilbur Ross said there was "no longer a very precise date" as to when talks would end and that the tariffs went into effect at midnight Thursday as a result.
"I don't think in any way the USA is abandoning its leadership in the global economy, quite the contrary. It was not. We believe in the G7, it's an important group", Mnuchin said at his own news conference.
Trump had originally imposed the tariffs in March - saying a reliance on imported metals threatened national security - but he exempted Canada, Mexico and the European Union to buy time for negotiations.
Chairing the meeting, Mr Morneau allowed participants to register grievances with Mr Mnuchin one at a time, according to a Canadian source.
Canadian Prime Minister Justin Trudeau had also said Thursday that US Vice President Mike Pence had insisted on including a "sunset" privision - which would require the trade pact's renewal in five years - as a precondition for a meeting to handle out final details.
Canada responded by imposing $16 billion worth of tariffs on the U.S. "Highly restrictive on trade!" he wrote.
"The fact that the president has moved forward with these tariffs is not just going to hurt Canadian jobs", Trudeau said.
China has threatened to hit back with tit-for-tat tariffs on tens of billions of dollars in U.S. goods - as have Canadian, EU and Mexican authorities.
The complaints came on the eve of a visit by Ross to China to try to secure long-term purchases of U.S. farm and energy commodities to help shrink the United States trade deficit and avert a looming tariff war between the world's two largest economies.
"But if you take the European Union and you see the kind of tariff they charge, and then we don't, that's called "not fair trade".
German Finance Minister Olaf Scholz said G7 countries also told Mnuchin about their opposition to new USA sanctions on Iran, which will affect European companies.
Still, Korea may not be safe from protectionism by the Trump administration, which slapped antidumping duties on Korean steel tubes and wire rods in April and May.