Trump accused Canadian Prime Minister Justin Trudeau of making "false statements", and said the U.S. is looking into automobile tariffs.
Citing Chinese philosopher Confucius, Navarro said, "If you make a mistake and don't correct it, that's a mistake".
Peter Navarro says his job was to send a "signal of strength" after Trudeau's post-G7 news conference sent the USA president into a fit of pique that threw the summit into disarray.
Following Trump's departure from the G7 summit, Trudeau said Saturday at a press conference that US steel and aluminum tariffs against Canada on national security grounds were "kind of insulting" and that Canada "will not be pushed around".
Several leaders from the G-7 meeting - including Germany's Angela Merkel, Britain's Theresa May and France's Emmanuel Macron - either expressed support for Trudeau or criticized Trump.
"He's giving a news conference about how he will not be pushed around by the United States".
Trump fired off a volley of tweets on Monday further venting anger at North Atlantic Treaty Organisation allies, the European Union and Trudeau.
The Canadian leader would likely argue, however, that not only does he lead one of the US's closest allies, but also that he did no such thing in negotiations with Trump.
However, the office of the U.S. Trade Representative has said the United States ran an $8.4 billion trade surplus with Canada in 2017.
Picture of Trump, G7 leaders goes viral
It showed a seemingly glowering German Chancellor Angela Merkel and several other leaders appearing to confront a seated Mr Trump .
Trump says Trudeau "probably didn't know that Air Force 1 has about 20 televisions". And I say, 'Push him around?
In Vermont, where Trump is particularly unpopular, a few choice words from the president won't keep people away from a popular weekend getaway on either side of the border, says one keen observer. "In conveying that message I used language that was inappropriate".
On Tuesday, Trump barely let up, telling reporters in Singapore, after his summit with North Korea's Kim Jong Un, that while the G7 summit was "good" Trudeau's critical comments would cost Canada "a lot of money".
In the same set of tweets, Trump said: "Justin acts hurt when called out!"
The insults stemmed from a closing G7 press conference on Saturday in which Trudeau called United States steel and aluminum tariffs "insulting" and pledged to proceed with previously announced retaliatory tariffs. He learned. You can't do that. "Our Tariffs are in response to his of 270% on dairy!"
If the USA imposes a 25 per cent tariff on those exports, suddenly they don't make much economic sense, said Kristin Dziczek, vice president of industry, labour and economics at the Center for Automotive Research in Ann Arbor, Mich.
"From the beginning we have said that our approach would be to hope for the best, to work for the best possible outcome but always be prepared for the worst, to have a Plan B, C, D, E and F - and maybe to the end of the alphabet".
"If it goes on for a while - and it would have to go on for a while - people might change their views, but I don't think this one incident is likely to have that effect".