A view of the storage area of galvanized coiled steel at ThyssenKrupp steelworks on January 17, 2018 in Duisburg, Germany.

"We strongly regret this step, which appears to represent a blatant intervention to protect U.S. domestic industry and not to be based on any national security justification," said European Commission President Jean-Claude Juncker in a statement.

Trump on Thursday announced that the United States will impose a 25 percent tariff on steel imports and a 10 percent tariff on aluminum imports as early as next week.

"The EU has been a close security ally of the U.S. for decades. We will not sit idly while our industry is hit with unfair measures that put thousands of European jobs at risk," said Juncker.

The European Commission is the executive branch of the European Union.

The Commission next will take the matter to the World Trade Organization, the statement said. The WTO refused to comment on the news when contacted by CNBC.