In a tweet sent Sunday while en route to Singapore, Trump pointed specifically to Canada's 270% tariff on dairy the origin of his frustrations with Canada.
Trump said that he withdrew the USA from the G-7's joint statement because of that slight.
Prime Minister Trudeau on the other hand, did not balk at the statements but instead remained professional and mature - which is to be expected from a leader of one of the most respected and democratic countries in the world.
The leaders of Canada and the United States are locked in an ugly, escalating public dispute over trade barriers, tariffs and how they think they world should resolve its problems.
The top White House economic adviser accused Canada's prime minister on Sunday of betraying Trump with "polarising" statements on US trade policy that risked undermining the American leader on the eve of a historic summit with North Korea.
"Sorry, we can not let our friends, or enemies, take advantage of us on trade anymore".
Based on Justin's false statements at his news conference, and the fact that Canada is charging massive Tariffs to our U.S. farmers, workers and companies, I have instructed our U.S. Reps not to endorse the Communique as we look at Tariffs on automobiles flooding the U.S. Market! A former US ambassador to Canada called on Trump trade adviser Peter Navarro to apologize for saying "there's a special place in hell" for Trudeau, whom he accused of practising "bad-faith diplomacy" at the weekend G7 summit in Quebec.
Trudeau has vehemently opposed the imposition of tariff on U.S. import of Canadian steel and aluminium and has threatened with retaliatory measures.
President Donald Trump's top economic adviser says Canadian Prime Minister Justin Trudeau "really kind of stabbed us in the back" when Trudeau said at the end of the Group of Seven summit that Canada wouldn't be pushed around by the USA and its trade tariffs.
The prime minister has kept a low profile since Trump called him "very dishonest and weak" and withdrew support for a Group of Seven communique reached at the summit Trudeau hosted in Quebec on Saturday.
Trump's chief economic adviser said the United States pulled out of supporting the communique because the president was enraged by Canadian Prime Minister Justin Trudeau.
G7 members Germany and France said they stood by the communique despite Trump's decision.
It's a startling attack on the leader of the US neighbor and ally. "But it did not start with this G7, but with the election of Donald Trump", said a European official.
"The European Union will continue to stand up for an global, rules-based, multilateral system". Nearly 70 percent of the steel used in the United States already is produced here, and our nation can never be self-sufficient in aluminum production because the bauxite used to make the metal is not mined here.
Trump's top economic adviser, Larry Kudlow, suggested Trump saw Trudeau as trying to weaken his hand before the summit with North Korea's Kim Jong Un, saying the president won't "let a Canadian prime minister push him around".
Canadian officials have stressed the two countries' extensive trading relationship and pointed out that Canada is the top export destination for 35 US states and that 9 million jobs in the United States depend on trade with its northern neighbour.
In retaliation, all three allies vowed to impose retaliatory tariffs on scores of USA products.
Trump's attacks have Canadian businesses that use aluminum and steel very anxious, said Ontario Conservative MP John Brassard, who added that there is real concern that there will be serious job implications in very short order.