US media report that the Department of Justice has launched an antitrust investigation into Nippon Steel's bid to purchase US Steel. Japan's largest steelmaker announced in December that it planned to buy the US company for about 14 billion dollars.
Online newspaper Politico broke the news of an in-depth probe on Wednesday, citing sources with direct knowledge of the matter.
Politico says the antitrust investigation focuses on a plant in the southern state of Alabama, jointly owned by Nippon Steel and Luxembourg-based ArcelorMittal. The plant competes directly with US Steel, particularly for automotive clients.
Nippon Steel's takeover bid is already under scrutiny by the Committee on Foreign Investment, a US panel that looks into national security issues.
President Joe Biden voiced opposition to the merger plan last month, saying US Steel must remain domestically owned and operated.
His Republican rival, Donald Trump, says he will block the deal if he wins the November election.