Foreign Minister Chrystia Freeland told reporters the measures would be met with "retaliation" as the clash between neighbouring nations rumbles on.
She said: "Canada will not change its mind when it comes to the illegal and absolutely unjustified application of tariffs on steel and aluminium, not only coming from Canada, but on the steel and aluminium sold by all the G7 allies who are assembled here."
Furious Trump will snub his allies and leave the G7 Summit several hours early – so he can prepare for Tuesday's showdown with Kim Jong-un.
The US President is currently embroiled in a vicious Twitter spat with Justin Trudeau and Emmanuel Macron over trade tariffs.
The row comes as leaders of the US, Canada, France, Germany, Japan, Italy, the UK and the EU today began arriving for the G7 summit in Canada.
Trump labelled Canadian Prime Minister Trudeau "indignant" after he and Macron angered him with their comments in a press conference yesterday.
According to CNN, Trump yesterday wanted to cancel his appearance at the G7 Summit completely, asking his advisers what the point of his attendance would be.
The only reason he is still going, the broadcaster reported, is because to cancel would make him look like he's hiding from a fight he picked.
Other sources said his focus was now entirely on Tuesday's historic summit in Singapore with North Korean tyrant Kim Jong-un, and his need to prepare for this.
By leaving early, Trump is missing discussions about climate change and the environment – two issues he cares little for.
Trump's Twitter row with the pair started yesterday when Trudeau and Macron warned him that attempts to protect American production put "people's jobs on the line".
Trudeau said: "American jobs are on the line because of his actions and because of his administration. When we can underscore this, and we see that there's a lot of pressure within the US, perhaps he will revise his position."
Macron added: "A trade war doesn't spare anyone. It will start to hurt American workers, the cost of raw materials will rise and industry will become less competitive."
He later added on Twitter: "The American President may not mind being isolated, but neither do we mind signing a 6 country agreement if need be.
"Because these 6 countries represent values, they represent an economic market which has the weight of history behind it and which is now a true international force."
But Trump fired back in a series of tweets, labelling Trudeau "indignant" and warning: "(I) look forward to seeing them tomorrow."
He continued: "Why isn’t the European Union and Canada informing the public that for years they have used massive Trade Tariffs and non-monetary Trade Barriers against the U.S. Totally unfair to our farmers, workers & companies.
"Take down your tariffs & barriers or we will more than match you!"
The European Commission has confirmed it intends to hit back with retaliatory tariffs from July on US imports ranging from jeans to bourbon whiskey.
Meanwhile, Trump is said to have insulted Theresa May, moaning privately about her "school mistress" tone and complaining she's too politically correct, according to a former White House official.
The source, who has sat in on meetings between the pair, also revealed he dislikes how May launches into policy detail rather than general chat, and makes frequent demands of him.
The PM is set to have formal meetings with the leaders of all the G7 countries at the group's summit in Canada – except Trump.
Despite the threat of tit-for-tat trade reprisals threatening to overshadow the meeting, Mrs May will use the summit to call on internet giants to do more to remove content showing violence against women.
She will tell her counterparts they must work with the tech industry to make the internet a place where women are not subjected to rape threats, harassment or cyberstalking.
Other clashes between Trump and his allies are likely to occur over the Iran deal he recently scuppered and climate change.
The summit will also be the first major outing for new Italian Prime Minister Giuseppe Conte, who has been selected to head up a coalition comprised of Italy's alternative, anti-EU political parties.
What is the G7 Summit?
The Group of Seven (G7) is an informal grouping of seven of the world’s advanced economies, as well as the EU and European Commission.
They consist of Canada, France, Germany, Italy, Japan, the United Kingdom and the US, and the presidency rotates every year.
It offers the leaders of these nations a chance to come together and tackle the most challenging global issues of the time.
What will they discuss?
This year's president is Canadian Prime Minister Justin Trudeau and he's announced five key themes.
They are: Investing in growth that works for everyone; preparing for jobs of the future; advancing gender equality and women's empowerment; working together on climate change, oceans and clean energy; and building a more peaceful and secure world.
However, the reality is much of the behind the scenes discussions will centre around Trump's looming trade war, a move likely to affect the entire global economy if he makes good on his threats and triggers it by imposing tariffs on imports.
What is the looming trade war?
This refers to Trump's plans to attack other countries' trade by imposing quotas and tariffs on products the US buys and imports from abroad.
He hopes imposing these tariffs on, for example, imported steel and aluminium, will protect US jobs and manufacturing at home.
Trump has also mentioned many times he wants to redress the US's large tax deficit. This term refers to the difference between how much your country buys from another country, compared with how much you sell to that country.
Source: Read Full Article