The decision to slap tariffs on steel and aluminum from the European Union is expected as early as Thursday morning, which would be a day ahead of a Friday deadline.
The U.S. Commerce Department and U.S. Trade Representative's Office did not immediately respond to requests for comment, according to the Wall Street Journal.
President Trump on March 23 imposed a 25 percent tariff on steel imports and a 10 percent tariff on aluminum, but granted temporary exemptions to the EU, Canada, Mexico, Brazil, Australia and Argentina.
Trump made the move to protect U.S. steel and aluminum producers on national security grounds, using a 1962 trade law to put the protections in place.
The European Commission, which coordinates trade policy for the 28 EU members, has said the bloc should be permanently exempted from the tariffs since it was not the cause of overcapacity in steel and aluminum.
In retaliation, the EU will set duties on $3.4 billion of U.S. exports, including peanut butter and denim jeans, if its metals exports to the United States worth $7.5 billion are subject to tariffs.
Economists say the standoff with the EU could tip toward a trade war, particularly after Trump last week launched another national security investigation into car and truck imports that could lead to new U.S. tariffs.
The Trump administration has given permanent metals tariff exemptions to several countries including Australia, Argentina and South Korea, but in each case set import quotas.
Friday's deadline for exemptions also affects Mexico and Canada, which are in negotiations with the United States on the North American Free Trade Agreement.