US media report that President Joe Biden is preparing to block an attempt by Japan's top steelmaker to acquire US Steel. The planned acquisition by Nippon Steel is facing growing bipartisan political opposition.

Biden as well as Vice President Kamala Harris and former president Donald Trump, rivals in the US presidential race, have said they will not allow the deal to go through.

The Washington Post and other US news outlets report that Biden is close to formally announcing that he will prevent the planned acquisition.

Quoting sources, the Post says that Biden has not received a recommendation from the Committee on Foreign Investment in the United States. The committee has been investigating the proposed acquisition and assessing the deal's impact on US national security.

The paper says the decision would be a "stunning rejection" of a deal proposed by a US ally, and one that has generated major political controversy ahead of the November election.

In a comment, Nippon Steel says it strongly believes the US government will properly assess the deal in accordance with the law. It also says they have clearly conveyed to the US government that the acquisition would not pose a threat to American national security.

Meanwhile, the head of US Steel has warned of consequences if the deal "falls through." CEO David Burritt told the Wall Street Journal that a plant would close and workers could lose their jobs.

He also said the company would look to move its Pittsburgh headquarters to the southern US.

US Steel shares closed 17 percent lower in New York on Wednesday from Tuesday's finish. At one point following the release of the Washington Post report, it sank 24 percent.