German Chancellor Angela Merkel has been pictured standing with her hands firmly planted on a table staring down at Mr Trump, who is seated with his arms folded and eyes glaring.
The striking image from the two-day summit, which has now gone viral after it was tweeted by Mrs Merkel's press team, lays bare the huge divisions in the group, with Prime Minister Theresa May, French President Emmanuel Macron and Japanese PM Shinzo Abe also leaning in on Mrs Merkel's side.
It comes as Donald Trump used his Twitter account to launch an angry attack against his key allies saying the US “paid close to the entire cost of NATO” to help countries that “rip us off on trade”.
Responding to the threat of new tariffs against the US, he said: “Fair trade is now to be called fool trade”.
The Republican firebrand also lashed out against Canada’s Prime Minister Justin Trudeau saying he “acts out when called out”.
The US leader, who is in Singapore for a landmark summit with North Korean dictator Kim Jong-un, said America was paying more towards the cost of NATO than fellow members.
He said his nation gets “unfairly clobbered” on trade despite “protecting Europe at a great financial loss”.
Mr Trump tweeted: “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!
“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! $800 Billion Trade Deficit...
“And add to that the fact that the U.S. pays close to the entire cost of NATO-protecting many of these same countries that rip us off on Trade (they pay only a fraction of the cost-and laugh!). The European Union had a $151 Billion Surplus-should pay much more for Military!
“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!”
Mrs Merkel quickly retaliated saying Mr Trump's tweets were "depressing" and "sobering".
She said: "We cannot let ourselves be pulled over the barrel."
Tensions between the US and the EU saw the G7 summit end in chaos after Mr Trump refused to sign the joint statement of world leaders.
The anger between the two sides escalated after President Trump relentlessly attacked the EU for treating the US as its own "piggy bank".
He declared that the "gig was up" during a summit that played out amid arguments over trade deficits and tariffs.
He blamed Canadian tariffs on US goods and "false statements" by Mr Trudeau, saying the Canadian was "so meek and mild" during the summit then hit out after he left, which Mr Trump said was "very dishonest & weak".