But they appeared to win no quick concessions.
"It's extremely regrettable and I'd like to work on the Americans to exempt us", Hiroshige Seko, Japan's minister of trade and industry, told a press conference.
"We are reaching out to people in the United States and asking 'Are you aware that you run a steel trade surplus with Canada?"
Trump, stating that US companies and their labor force have always lost against friends and enemies at trade agreements signed by the previous White House administrations and the country has thus lost its iron and steel and aluminum sectors, with the slogan "Make America Great Again", points out that it is time for change. Under World Trade Organization rules, such counter-measures have to be in place within 90 days of the USA tariffs entering force.
The actual formal documents specifically state that Canada and Mexico are a special case, given the continent's shared commitment to mutual security, an integrated defence industry and the shared fight against dumped steel and that the best way to address US concerns - "at least at this time" - is by continuing discussions. Not fair or sustainable.
Asked why auto manufacturers are so opposed to tariffs if the impact on their costs is minimal, as the administration is arguing, newly elevated Trump trade adviser Peter Navarro was dismissive.
As he blitzed through the industrial Midwest as a presidential candidate, Donald Trump pitched himself as the savior of the "forgotten" men and women in communities where factories had been shuttered and jobs were moved overseas.
Republican lawmakers are not happy about President Donald Trump's import tariffs on steel and aluminum.
One analyst said that a substantial number of workers in the steel industry could lose their jobs due to the tariffs. "We are deadly serious" about solving what the USA sees as unfair trade in steel and aluminum.
USA agriculture trade groups have sharply criticized the White House's push to move ahead this week with import tariffs of 25 percent on steel and 10 percent for aluminum, warning that retaliatory actions could target US exports of grain and oilseeds.
Key U.S. trading partners and businesses have warned the tariffs could backfire, provoking a trade war and hurting allies like the European Union and Japan more than China, their main target. Both countries had warned of retaliatory measures if they were not exempt. He was apparently referring to the European Union threats of retaliation.
Trump suggested there would be good news just around the corner for a renegotiated NAFTA - a trade deal he has consistently dissed as bad for America.
Trump pushed back as he visited western Pennsylvania, in the heart of United States steel country, where he boasted of his tariffs and denounced low-quality imports.
While Trump has been a big backer of the US coal industry, it is possible that his new tariffs could backfire, hurting USA coal exports while boosting those from China. AK Steel was down 4.4% at $5.21 at the time of writing. China is the world's largest producer of "met coal", but it consumes it all and buys more from overseas, including from the U.S. Australia is also a major exporter of metallurgical coal.
European steel and aluminum associations have warned that the USA tariffs could cost their sectors thousands of jobs.