There will be a meeting at the end of March to discuss a "proportionate response" but there will be a clear objective - according to Tusk - to keep "world trade alive".
China warned Thursday it was ready to respond to US tariffs if they materialize.
Even some members of Congress who have steel or aluminum factories in their states are worried about the possible tariffs.
Next week, Trudeau will tour regions of Canada that are heavily reliant on the steel and aluminum industries in a show of solidarity for those who would be hurt most by stiff U.S. tariffs. Such deficits have been frequently mentioned by Trump as a reason for tariffs.
Trump plans to impose a duty of 25 per cent on steel and 10 per cent on aluminum to counter cheap imports, especially from China, that he says undermine U.S. industry and jobs.
Despite the apparent reprieve, Ottawa is leaving nothing to chance, preparing a plan to hit the United States with retaliatory duties on strategic products just in case it doesn't get an exemption for the looming global trade war.
Trump maintained a strong stance against the EU on Tuesday, when he accused the block of "very, very unfair" trade. There were regulations to drop.
Jack Daniel's maker Brown-Forman sank after CEO Paul Varga said his company "could be an unfortunate and unintended victim" of more hostile trade. "We are eager to work with you in pursuing a workable, targeted approach that achieves our shared goal", they wrote. "We must act soon!" The Post added that Trump also asked Republican Senator Marco Rubio to come, but he couldn't make it due to a scheduling conflict.
Trump is also considering potential trade sanctions against China under a "section 301" investigation into its intellectual property practices and pressure on foreign companies for technology transfers.
"Whatever the case, we cannot ignore the risk of protectionism", Ayako Sera, market economist at Sumitomo Mitsui Trust Bank.
For the first year after Donald Trump's election, the GOP split that emerged during the campaign festered. I think there's something like one third of all Trump's appointees in 2017 resigned which is probably more than have resigned in total from the last thirty years' worth of American presidents.
"We won't drive the economy to over 3 per cent growth or continue to create jobs if we go down this path", said Mr Donohue, the chamber's president and chief executive.
"Concerns about the US tariff should ease today following the comments from the White House", said Masahiro Ichikawa, senior strategist at Sumitomo Mitsui Asset Management.
In contrast, the fall in steel exports extended a steady decline in recent years as local demand has grown and China reins in its domestic steel capacity to curb stifling smog.
The president said on Monday that Canada and Mexico would only be excluded after the successful renegotiation of Nafta.
Declining issues outnumbered advancing ones on the NYSE by a 1.23-to-1 ratio; on Nasdaq, a 1.66-to-1 ratio favored advancers.
Trump plans to impose a 25 percent tariff on steel imports and a 10 percent tariff on aluminum imports.
Imported steel and aluminum would become more expensive because of tariffs.
Discount retailer Dollar Tree's fourth quarter results disappointed investors, and so did its forecasts for the current year. The announcement represents a reversal to Trump's previous pledge of imposing the tariffs without exceptions.
President Donald Trump's team played down talk of a trade war Wednesday as it fought to limit a financial market sell-off, promising a quick decision on contentious tariffs that prompted a popular economic advisor to the president to quit.