During a Senate Commerce committee hearing Thursday, Lighthizer said the European Union, along with Brazil, South Korea, Argentina and Australia, will be exempted while they discuss potential alternatives with the U.S. 

"There are countries with whom we're negotiating, and the question becomes the obvious one that you think, as a matter of business, how does this work? So what (the president) has decided to do is to pause the imposition of the tariffs with respect to those countries," Lighthizer told senators. 

Separately, American Iron and Steel Institute president and chief executive Thomas J. Gibson reiterated the need for the tariff during an industry conference earlier this week.  

Speaking during the annual S&P Global Platts Steel Markets North America conference in Chicago, Gibson said that despite the imposition of approximately 160 steel-related trade measures, U.S. producers are still being challenged by unfairly traded imports. 

“As soon as we win a case, we see imports of that product shift to another country, and there are many products from countries that are not covered by orders.” 

He also said that although the U.S. industry is committed to efforts to solve the underlying problem of global excess capacity through discussions sponsored by the OECD’s Global Forum on Steel Excess Capacity, action needs to be taken in the near term. 

“While we’re committed to the forum and view its work as meaningful, the forum alone will not provide any near-term remedies to the industry. It needs a push,” he said.