This then lead to Trump claiming that Trudeau was "meek and mild" and one of Trump's top advisers saying there was a "special place in hell" for Trudeau.
But while he acknowledged the tensions between Canada and the US playing out in a trade dispute triggered by American tariffs on steel and aluminum imports, Trudeau said the USA remains a close friend and trading partner regardless of who is prime minister or president.
Relations between President Trump and Prime Minister Trudeau continue to grow sour with Trump now claiming that Trudeau's stance on trade discussions was a "mistake" that would cost Canada "a lot of money". He wrote Trudeau ahead of the summit expressing "growing frustration" with the fact the two per cent target is still not being met by the majority of alliance nations. Trump's trade adviser Peter Navarro went as far as telling a USA talk show that there was "a special place in hell" for Trudeau, though he later walked back the remark.
"I speak with [Trump] fairly regularly and I look forward to seeing him again", he said.
The conflict gained traction when Trudeau promised to hit back with retaliatory measures. The likelihood of a trade war between the US and Canada appears to be on the rise and both sides are mulling more trade barriers. Members don't pay dues, although they do contribute to common military and civilian programs - and Washington pays nearly one-quarter of those costs.
At the same time, the North Atlantic Treaty Organisation chief said more needs to be done, and that Canada and its European allies "should not increase defence spending to please the United States", but because meeting the two per cent target is important for their own security and defence.
Trump says North Atlantic Treaty Organisation members have agreed to spending increases
It remains to be seen whether Trump really meant it about consistency, when it comes to soccer, however. Trump listed the top US arms makers, Lockheed Martin Corp, Boeing Co and Northrop Grumman Corp by name.
Trudeau said Canada will not double its defence budget to get to that mark.
Canadian Prime Minister Justin Trudeau said his country is offering to lead NATO's new military training mission in Iraq for the first year and stands ready to provide 250 troops plus helicopters for the effort.
Questioned repeatedly about Trump's attacks on European allies and Canada, NATO Secretary General Jens Stoltenberg acknowledged the trans-Atlantic differences but refused to say whether the United States leader's attacks are damaging the alliance.
"We are two countries that are more closely integrated on trade and security on people-to-people ties than any two countries in the world".
NATO Secretary General Jens Stoltenberg applauded Canada and European allies Tuesday for having reversed years of cuts by investing more in defence and contributing more troops and equipment to collective security - even as he pushed back against suggestions the alliance was in trouble.