(CNN) US President Donald Trump continued to excoriate his Group of 7 summit allies in a series of tweets from Singapore, where he is due to meet North Korean leader Kim Jong Un in a historic summit Tuesday.

The tweetstorm is the latest fallout from a bad-tempered G7 summit in Quebec, Canada, in which the President found himself at odds with many of the leaders present, largely over his planned tariffs on a range of goods, including steel and aluminum.

Less than 24 hours before his meeting with Kim, Trump found time to lambast what he sees as unfair trade practices among the other six industrialized democracies at the summit.

"Fair Trade is now to be called Fool Trade if it is not Reciprocal. According to a Canada release, they make almost 100 Billion Dollars in Trade with US (guess they were bragging and got caught!). Minimum is 17B. Tax Dairy from us at 270%," he wrote in the first of five tweets relating to the weekend's summit.

Fair Trade is now to be called Fool Trade if it is not Reciprocal. According to a Canada release, they make almost 100 Billion Dollars in Trade with U.S. (guess they were bragging and got caught!). Minimum is 17B. Tax Dairy from us at 270%. Then Justin acts hurt when called out!

"Then (Canadian Prime Minister) Justin (Trudeau) acts hurt when called out!"

He followed up by asking why the US should "allow countries to continue to make "massive trade surpluses," asserting that it is "not fair to the people of America" and that the US is suffering under a "$800 billion trade deficit."

Trade war on horizon

The G7's other attendees fear a looming trade war over the Trump administration's move to impose steep tariffs on steel and aluminum imports from the European Union, Canada and Mexico.

Those tensions boiled over on Saturday, with Trudeau and European leaders reaffirming plans to institute retaliatory measures and Trump lashing out in response by refusing to endorse the the G7 communique, a negotiated statement on shared priorities among the group.

Speaking to reporters from her home country, German Chancellor Angela Merkel called the US' retraction of support for a shared statement "sobering and somewhat depressing."

Merkel, whose office over the weekend released a photo of leaders and aides which illustrates the divide between Trump and his allies, said she had "tried hard to find a compromise and we fought hard for it ... this was an important announcement."

Trump had earlier lashed out at Canadian leader Justin Trudeau for what he said were "false statements" at a news conference and said the US would not endorse the G7 communique.

Although it is unclear which of Trudeau's statements Trump was calling false, Trudeau said in a news conference Saturday that Canada will "move forward with retaliatory measures" on July 1 in response to the Trump administration's decision to impose tariffs on steel and aluminum imports from Canada, the European Union and Mexico.

Trump revisits NATO complaints

Trump's post G7 tweets also revisited an old bugbear -- the funding of the NATO military alliance.

The EU has "a $151 billion surplus" which it should use to fund "military," said Trump Monday, referencing what Trump believes is the US' outsized financial contribution to NATO.

"Germany pays 1% (slowly) of GDP towards NATO, while we pay 4% of a MUCH larger GDP. Does anybody believe that makes sense? We protect Europe (which is good) at great financial loss, and then get unfairly clobbered on Trade. Change is coming!"

Around an hour later, he returned to Twitter with a final, parting shot.

"Sorry, we cannot let our friends, or enemies, take advantage of us on trade anymore. We must put the American worker first!"

JUST WATCHED Navarro: Special place in hell for Trudeau Replay More Videos ... MUST WATCH Navarro: Special place in hell for Trudeau 00:56

Members of Trump's inner circle continued the attacks, with both chief economic adviser Larry Kudlow -- who said that Trudeau had "stabbed us in the back" -- and Peter Navarro, Trump's trade adviser, directing a series of stinging comments at the Canadian leader.

JUST WATCHED Kudlow: Canadian PM Trudeau should apologize Replay More Videos ... MUST WATCH Kudlow: Canadian PM Trudeau should apologize 04:38

"There's a special place in hell for any foreign leader that engages in bad faith diplomacy with President Donald J. Trump and then tries to stab him in the back on the way out the door," Navarro said, during an appearance on Fox news.

"And that's what bad faith Justin Trudeau did with that stunt press conference. That's what weak, dishonest Justin Trudeau did, and that comes right from Air Force One," said Navarro.

Navarro added that while these were his own words, they reflected the "the sentiment that was on Air Force One." Navarro also said Trump attending the G7 in Canada was a "courtesy" to Trudeau and that the President had "bigger things on his plate" in Singapore.