US president expected to announce decision to block proposed sale of Pittsburgh-based steelmaker as early as Friday.

United States President Joe Biden has decided to block the proposed takeover of US Steel by Japan’s Nippon Steel, US media has reported.

Biden is expected to announce his decision to scuttle the $14.9bn sale on national security grounds as early as Friday, The New York Times, The Washington Post and Bloomberg reported, citing people familiar with the matter.

Biden’s decision comes after the Committee on Foreign Investment in the United States last month failed to reach a consensus on the possible national security risks of the deal, and just weeks before he hands control of the White House to US President-elect Donald Trump.

Biden had been widely expected to block the sale of the Pittsburgh-based steelmaker to Japan’s largest steel producer after opposing the proposal during his ill-fated re-election campaign.

Trump, who takes office on January 20, also opposed the deal, describing the proposed sale as “a horrible thing”.

The proposed sale was seen as an important election issue in the key swing state of Pennsylvania, which flipped from Trump to Biden in 2020 and back to Trump in November.

The United Steelworkers labour union (USW) lobbied strongly against the sale, describing it as “nothing more than corporate greed, selling out American workers and jeopardising the long-term future of the domestic steel industry and our national security”.

Under the proposed sale, which was overwhelmingly backed by shareholders of US Steel, the combined company would have become one of the world’s largest steel producers.

US Steel would have become a subsidiary of Nippon Steel but kept its name and its headquarters in Pittsburgh.

Biden’s decision could strain relations with Japan, one of the closest US allies in Asia and a key partner in Washington’s efforts to counter China.

Japanese Prime Minister Shigeru Ishiba in November wrote to Biden asking him to approve the deal to avoid damage to ties between the sides, the Reuters news agency reported, citing people familiar with the matter.