Senior administration officials had reservations about calling Nippon Steel’s takeover proposal a “national security risk.”

President Joe Biden has blocked the nearly $15 billion proposed deal for Nippon Steel of Japan to purchase Pittsburgh-based U.S. Steel — affirming his earlier vow on the presidential campaign trail to prevent the acquisition of Steeltown USA's most storied steel company.

The president said he was moving to protect national security in deciding the fate of the iconic Pennsylvania-based company, which became a contentious political issue in an election year.

The move comes after a year of political and economic drama. It leaves the future of the once-iconic American business in doubt.

Shares of U.S. Steel sank Friday as President Joe Biden blocked the $14.1 billion sale of the iconic American company to Japan's Nippon Steel.

The companies condemned the president's decision and hinted at taking legal action, while U.S. Steel's CEO accused Biden of "political corruption."

President Biden is blocking the proposed $14 billion acquisition of U.S. Steel by Nippon Steel. Fox - 10 Phoenix Fox - 10 Phoenix

Joe Biden said the deal would create "risk for our national security and our critical supply chains." President-elect Trump also opposed the takeover.