President Trump doubled down on his criticism of Canada and the European Union (EU) late Sunday amid the ongoing fallout from a tense meeting between members of the Group of Seven (G-7) industrialized nations this past weekend.

"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!" Trump tweeted, referring to Canadian Prime Minister Justin Trudeau.

"Why should I, as President of the United States, allow countries to continue to make Massive Trade Surpluses, as they have for decades, while our Farmers, Workers & Taxpayers have such a big and unfair price to pay? Not fair to the PEOPLE of America!" he added, before repeating his common refrain of an $800 billion trade deficit.

The president is currently in Singapore, where he is set to meet for historic talks with North Korean leader Kim Jong Un. But the lead-up to the much-anticipated meeting has been overshadowed by the aftermath of the G-7 summit, which saw Trump warning some of the U.S.'s closest allies that they must remove trade barriers or face consequences.

His most recent tweets are part of an ongoing argument Trump has made that Canada and other countries have been taking advantage of the U.S. In fact, contrary to his tweet, the U.S. ran a trade deficit in 2017 of $568.4 billion, according to the Census Bureau and Bureau of Economic Analysis. Meanwhile, Canada is the top export market for the U.S., which had an $8.4 billion surplus with the country in 2017, according to the Office of the United States Trade Representative.

Trump on Sunday went on to criticize the EU for having a $151 billion trade surplus with the U.S., when in fact it is $101 billion, according to The Associated Press. He also repeated his frequent criticism of NATO members - especially Germany - for not paying what he claims is their fair share of defense spending.

He said that NATO nations should "pay much more for the Military," tweeting that "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."

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

His comments came after a new interview on Sunday in which German Chancellor Angela Merkel said the EU would follow through on its plan to implement retaliatory measures in response to Trump's recently announced steel and aluminum tariffs.

She also addressed Germany's defense spending, which has come under frequent fire from Trump, suggesting that the U.S. president had a point and that her country would start spending more.

Trump's comments come after a feud erupted between his administration and Trudeau. On Saturday, Trump criticized the Canadian leader after Trudeau announced that all G-7 nations at the summit over the weekend signed onto a joint communique.

The president blasted Trudeau and said the U.S. would not endorse the statement. Later, on Sunday, two of Trump's top advisers ramped up the criticism of the Canadian leader, with the White House's top trade adviser, Peter Navarro, saying there is a "special place in hell" for Trudeau.

Following the comments, numerous U.S. and foreign leaders publicly voiced their support for Trudeau and criticized Trump for picking a fight.

Canada, for its part, has also announced that it would implement countermeasures in response to Trump's tariffs.