Canada would then impose retaliatory tariffs on $C16.6 billion ($16.93 billion) worth of U.S. exports and those will stay in place until the United States lifts its own measures, Foreign Minister Chrystia Freeland said.
The European Union has already notified the World Trade Organization of plans to levy duties on about $7 billion worth of US exports in response, with the aim of collecting $1.6 billion in tariff revenue. It will also lodge a case with the World Trade Organization (WTO).
"These tariffs are an affront to the long standing security partnership between Canada and the United States", said Trudeau, as Ottawa hit back with retaliatory duties on U.S. imports worth up to $12.8 billion.
In the wake of the US slapping steep tariffs on imports of Canadian steel and aluminum, Justin Trudeau hit back, saying that he hopes common sense will prevail in trade dealing between the two countries.
Mexico said it would penalise USA imports including pork bellies, apples, grapes, cheeses and flat steel.
European officials, bracing for the tariffs, have threatened to retaliate against USA orange juice, peanut butter, kitchenware, clothing and footwear, washing machines, textiles, whiskey, motorcycles, boats and batteries.
"We are imposing dollar for dollar tariffs for every dollar levied against Canadians by the United States", he wrote.
The European Union is planning retaliatory tariffs on US steel and food goods in the coming weeks, once it calculates the exact cost to European Union companies of the USA tariffs.
U.S. Commerce Department data show Canada is the top source of U.S. imports of steel and aluminum, while Mexico is the U.S.'s fourth-largest provider of steel and 10th-largest of aluminum.
When asked how a tariff war would affect a US-UK trade deal, Fox said: "The US administration has made clear gains this week that they are very keen to see an agreement with the UK but regard steel imports as an European Union issue".
The United States has repeatedly suggested that the European Union should impose voluntary export quotas on steel and aluminum production.
The 25 per cent tariff on steel and 10 per cent tariff on aluminum will be imposed effective midnight.
Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto spoke by phone following the USA announcement.
The EU's trade chief was keen to stress she is not targeting any one side, with Beijing one of the driving forces behind Mr Trump's decision to impose tariffs.
Late Thursday, the White House said the USA had delivered a stark message to Mr. Trudeau.
European Union trade commissioner Cecilia Malmström added: "Today is a bad day for world trade".
"The American administration has made a decision today that we deplore", Trudeau said.
Several company representatives quietly acknowledged their concerns about the impact of a looming trade war involving steel and aluminum, and said they would be watching the issue closely.
Many trade experts argue the United States is hitting the wrong targets, as the worldwide glut of steel and aluminium is largely blamed on excess production in China. "They must open their markets and take down their trade barriers!" the President tweeted. "The fact that we took a tariff action does not mean that we can not have trade negotiations".