Trump on Friday said Australia would become the third country to be free from a 25 percent tariff on steel imports and 10 percent for aluminum.
Trump insisted there would be a fair process of negotiation, including talks of exemptions.
At talks in Brussels, economy ministers underlined that the European Union - the world's biggest trading bloc - supports free and open trade but that its 28 countries will respond if they are targeted by the USA tariffs, which are set to enter force next week.
Commerce Secretary Wilbur Ross will speak with representatives of the European Union about eliminating tariffs on USA imports, President Donald Trump said in a tweet on Monday morning.
"In some places, trade has been blamed for the pains of globalization, others use it as a scapegoat and insist that we can hide behind walls and borders", EU Trade Commissioner Cecilia Malmstrom said at a conference in Brussels on Monday.
"We are very concerned about the actions taken by China and the dumping of steel and aluminum on the global market", Trudeau said following a tour of a steel and aluminum plant.
As noted by Bloomberg's Leonid Bershidsky, Trump's gripes about the modest US deficit in trade with the EU are overstated; almost 60 percent of USA imports are "related party" goods and services produced by USA companies overseas, and American companies in Europe ($720 billion) significantly outproduced European companies in the US ($584 billion) in 2016. But he exempted Canada and Mexico and held out the possibility of excluding other allies.
Trump executive order will exclude Australia from new tariffs
Despite being one of the world's largest suppliers of raw commodity, iron ore, Australia is a small global exporter of steel. Australian steel and aluminium to the United States were worth just over $400 million a year ago .
The EU rejected Mr Trump's argument that the tariffs are required for national security reasons.
And Warner questioned whether tariffs will resurrect the U.S. steel industry the way Trump is boasting they will.
Over the weekend, Mr Trump argued that the U.S. has been abused economically by the European Union, saying they were "wonderful countries who treat the USA very badly on trade".
"Cherry-picking particular tariffs in one category, like looking just at vehicle tariffs on both sides, misses the whole picture, while not taking into account lower levels on other products does not give an accurate picture of tariffs in general", a Commission spokesman said. "It is bad for European citizens, for Dutch citizens, and it will turn out bad for U.S. citizens as well".
It was the second call in a week that Trudeau made to Trump on the tariffs issue. Canada has said that tariffs would hurt both the United States and Canada. The U.S., Canada, and Mexico wrapped up their seventh round of negotiations early this month.
'If they drop their horrific barriers & tariffs on USA products going in, we will likewise drop ours, ' he pledged in a tweet.
Trump and his trade officials have signalled in the past they are looking for more access to Canada's dairy market within a renegotiated NAFTA deal.