"I think that we've had a massive effort on tax reform in the United States which has had a incredible impact on the USA economy", Mnuchin said.
At the same time, Ottawa will challenge the "illegal and counterproductive" U.S. measures under the North American Free Trade Agreement (NAFTA) and at the World Trade Organization, said Freeland.
Malmstrom said overproduction from China, not Europe, was to blame for the glut of steel that prompted the United States action.
"We have important security and foreign policy relationships and although again there were discussions on trade, there were many, many areas that not only we agree on, we were completely united on", he said.
Trump announced plans for tariffs on foreign steel and aluminium in March, justifying them on national security grounds. Trudeau says he would still be happy to come down and see the president if there are no pre-conditions set.
If the US goes ahead with its tariffs, the European Union has threatened to impose retaliatory tariffs on USA orange juice, peanut butter and other goods in return.
President Trump on Saturday blasted critics who accused him of starting a trade war, saying the US has been losing the trade war for years.
"It is unfortunate because this is further weakening the transatlantic relations and it also increases the risk of severe turbulence in the markets globally".
Jean-Claude Juncker, president of the European Commission, said the European Union also will apply news tariffs on American goods, with the trading bloc signaling it would target products made in states represented by key Republican leaders.
The European Union will launch legal proceedings against the U.S.in the WTO on June 1.
"It is a sad day for worldwide trade", Guajardo said.
Mr Morneau has called that "absurd" because Canada is no security risk to the USA, and he warned the tariffs will destroy jobs on both sides of the border. We think on the contrary that global trade must have rules in a context of multilateralism.
Labour's shadow worldwide trade secretary Barry Gardiner earlier warned the UK Government to "strongly respond" to the move.
"We believe, as we have always said, it is a great outcome for the U.S. and for Australia". "Donald Trump is a bully and the only way to deal with a bully is to stand up and push back and we have to do that".
"We have to respond strongly to it and make it clear to him that we're not susceptible to the intimidation and the threats and the bullying that he's putting in place".
Former White House press secretary Anthony Scaramucci, also speaking to Radio 4, said with Mr Trump there was "always room for negotiation".
Earlier this week, Mr Trudeau said that killing the deal could be better than swallowing unfavourable revisions to the 1994 trade pact.