WASHINGTON (AP) -- The White House is signaling an openness to blocking the acquisition of U.S. Steel by Nippon Steel, as a government review of the proposed takeover by the Japanese company is on the cusp of ending.

The Washington Post reported Wednesday that President Joe Biden plans to stop the deal from going forward. A White House official, insisting on anonymity to discuss the matter, did not deny the report and said Biden still needs to receive the official recommendation from the Committee on Foreign Investment in the United States. That review could end as soon as this month.

Biden had already voiced his objections to the merger, backing his supporters in the United Steelworkers union who oppose the deal. The objection carries weight as U.S. Steel is headquartered in the swing state of Pennsylvania and is a symbol of Pittsburgh's industrial might in an election year where Republicans and Democrats alike are promising more domestic manufacturing jobs.

Vice President Kamala Harris, the Democratic nominee, came out against the deal this week. Former President Donald Trump, the Republican nominee, already said he would block the merger if he was still in the White House.

Stock in U.S. Steel fell roughly 19% on the news that Biden would stop the merger.