"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.
European Trade Commissioner Cecilia Malmström, who is currently touring Asia, said the problem facing the global steel and aluminum market is overcapacity caused by "non-market based production."
Malmström did not name any countries that are overproducing steel and aluminum. China has been criticized for years for dumping its state-subsidized, excess steel on Europe, the United States and other countries.
Such a tactic drives down prices to unsustainable levels for domestic producers. China denies that it engages in dumping, and it does not rank among the top 10 sources for U.S. steel imports, according to data from IHS global Trade Atlas. China is the fourth biggest exporter of aluminum to the United States.
"This can only be addressed at the source, and by working with the key countries involved. This go-it-alone action by the U.S. will not help," said Malmström.
"These U.S. measures will have a negative impact on transatlantic relations and on global markets. In addition, they will raise costs and reduce choice for U.S. consumers of steel and aluminum, including industries that import these commodities," she said. "The EU will seek dispute settlement consultations with the U.S. in Geneva at the earliest opportunity."