WASHINGTON — President Trump is preparing to sign off on new tariffs for steel and aluminum exports as early as Thursday, even amid more Republican objections and uncertainty about whether some countries may be exempted, according to two administration officials. 

FILE - In a Sept. 22, 2005 file photo a steel worker measures steel coils of ThyssenKrupp steel company in Duisburg, western Germany. Ordering combative action on foreign trade, President Donald Trump has declared that the U.S. will impose steep tariffs on steel and aluminum imports, escalating tensions with China and other trading partners and raising the prospect of higher prices for American consumers and companies.
Frank Augstein, AP

Late Wednesday, the White House was pulling together details of a formal ceremony as aides suggested some countries might be exempted from the tariffs, including Mexico and Canada.

But, adding to the confusion, Wednesday night when the White House released its schedule for Thursday, no signing ceremony was listed.

In a letter released Wednesday, 107 House Republicans led by Ways and Means Chairman Kevin Brady — the Texas Republican Trump has praised often for his management of the tax overhaul last year — urged Trump to “tailor” the tariffs to punish “bad actors who trade unfairly and hurt America” such as China.

Broad tariffs, they said, could have “unintended negative consequences to the U.S. economy and its workers,” especially when lower corporate tax rates were making American companies more competitive in global markets.

“Adding new taxes in the form of broad tariffs would undermine this remarkable progress,” they wrote.

Trump said last week that Canada and Mexico could avoid tariffs if they make concessions in ongoing negotiations to re-work the North American Free Trade Agreement.

White House officials said there has never been any doubt that Trump would follow through on last week’s pledge to put 25% tariffs on steel imports and 10% on aluminum imports.

White House spokeswoman Sarah Sanders said, “there are potential carve-outs for Mexico and Canada based on national security, and possibly other countries, as well, based on that process.”

White House trade adviser Peter Navarro told Fox Business Network that aides will be in the Oval Office at 3:30 p.m. ET “with a bunch of men and women from steel country and aluminum country coming in to see the president ... He'll sign the proclamations, and within 15 to 30 days, the tariffs go into effect.”

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Contributing: Herb Jackson, Gregory Korte