"It's more of the same jitters we had seen recently, with investors in this case fearing that a lack of confidence in the tariffs by Trump's own people", said Andre Bakhos, managing director at New Vines Capital LLC in Bernardsville, New Jersey.
The adviser, Peter Navarro, tells Fox Business that Trump intends to sign a proclamation including such a clause favoring the US neighbors. "He'll sign the proclamations, and within 15 to 30 days, the tariffs go into effect".
They say any tariffs should be targeted to minimize negative consequences.
The European Union has warned it could retaliate on United States imports, including products such as motorbikes, bourbon and jeans.
Opposition to the blanket tariffs mounted among lawmakers and the business community.
"It hurts the administration politically because trade wars, protectionism, they lead to higher prices for individual Americans", Phillips said.
They erased most losses as White House spokeswoman Sarah Sanders told a media briefing that the impending hefty United States tariffs on steel and aluminium imports could exclude Canada, Mexico and a clutch of other countries.
White House spokesperson Sarah Sanders said earlier the details would be made known by the end of this week.
Trump doubled down on his commitment to tariffs on Wednesday in a Tweet, citing the job losses and trade deficits that the USA has incurred for almost two decades. Trump's pledge to implement tariffs has also roiled financial markets and angered foreign allies.
EU Council President Donald Tusk hit straight back at Mr Trump, saying "Trade wars are hard to win and easy to lose". That scenario, Tom Donohue said, would endanger the economic momentum from the GOP tax cuts and Trump's rollback of regulations.
Earlier this week, Trump reaffirmed his belief in the importance of the U.S. steel industry and its relation to national security.
Tim Phillips, president of the Koch Brothers-backed Americans for Prosperity, noted that Trump narrowly won in Iowa and Wisconsin, two heavily rural states that could suffer if countries put in retaliatory tariffs on American agricultural goods.
Trump signaled other trade actions could be in the works.
The U.S. aluminum industry could satisfy more demand than it does today, but not all domestic demand, said spokesman Matt Meenan.
Net exports contributed 9.1 percent of China's GDP growth past year. "We're going to have very sensible relations with our allies", Ross said.
Treasurer Scott Morrison said Australia was proceeding in a calm and collected manner, and couldn't afford to take the tariff issue personally. Lawmakers like Roberts fear retaliation from foreign nations on US exports, and agriculture is primed to take a hit. Schumer, the Senate's top Democrat, is lending his voice to that of GOP leaders who have been critical of Trump's latest trade proposal. Canada President Justin Trudeau called Mr. Trump Monday evening to register his "serious concern". Although Cohn had a strong intellectual argument-What sense does it make to punish countries like Canada, when it is China that is dumping goods at artificially low prices in the US market?-he lost the political battle.
A former silver trader who sweet-talked his way into his first job at the New York Commodity Exchange and was later the second-highest-ranking executive at Goldman Sachs, Mr. Cohn understood the nuances of free markets and complex organizations, but was not locked into a specific worldview.
The President and White House have been looking to schedule a trip to the border "for a while", one source said.
Sen. Lamar Alexander, R-Tenn., said Trump had listened to him and others who disagree with the direction of the trade policies.
"And if we get that, then all is good with Canada and Mexico", he added. He says it's "not inconceivable that others could be exempted on a similar basis".
China, which ranks 11 among the largest sources of U.S. steel imports, cautioned that it was prepared to "make an appropriate and necessary response" should the United States impose the tariffs.
Congressional Republicans and industry groups are pressing the president to narrow his plan for across-the-board tariffs.
Even for Trump, this would represent a new level of policy chaos.
USA trade policy has always been written with the intent to give the president broad authority to handle global trade without Congress nitpicking the details.
Action that does not include exemptions risks retaliatory tariffs on USA exports - not least by Canada and Europe - and complicates already tough trade talks on Nafta.