By Yuka Obayashi and Ritsuko Shimizu

TOKYO, May 21 (Reuters) - Japan's Nippon Steel 5401.T remains committed to acquiring a full stake in U.S. Steel X.N, a senior executive said, adding that it is seeking a meeting with U.S. Treasury Secretary Scott Bessent to clarify President Donald Trump's stance on the deal.

The steelmakers face a May 21 deadline for the completion of a renewed national security review by the Committee on Foreign Investment in the US (CFIUS) of the proposed $15 billion merger, which was blocked by former President Joe Biden on national security grounds in January following a prior review.

In April, Trump directed the CFIUS to reassess the deal, raising hopes of a reversal, although he said in February the deal would take the form of an investment instead of a purchase. Trump is expected to decide the fate of the transaction by June 5.

"Our intention to pursue a full buyout remains unchanged," Nippon Steel Vice Chairman Takahiro Mori, a lead negotiator on the deal, told Reuters on Tuesday.

He said only full ownership would allow Nippon Steel to share its core technology and strengthen U.S. Steel, not in a joint venture.

"There is no free technology," Mori said.

He said Nippon Steel has requested a meeting with Bessent, who chairs CFIUS, to better understand Trump's position ahead of a final decision.

On Tuesday, Reuters reported that Nippon Steel plans to invest $14 billion in U.S. Steel's operations, including up to $4 billion in a new mill, if the Trump administration green lights its bid for the iconic U.S. company, according to a document and three people familiar with the matter.

Mori declined to comment on details of the CFIUS talks, but said any increase in investment would be tied to higher returns and would not strain the company's finances.

"This deal will make U.S. Steel and United States stronger," Mori said, adding that it aligns "100% with Trump's policy," by boosting foreign investment and domestic manufacturing.

"My view is, if President Trump fully understands (strategic significance), he will approve it," Mori said, noting plans to preserve U.S. Steel's name, headquarters, and integrated operations.

The majority of the new board of U.S. Steel would be American, with trade and manufacturing capacity issues overseen by three independent directors appointed by CFIUS, effectively the U.S. government, addressing national security concerns, he said.

The world's No.4 steelmaker expects net profit to fall 43% in the fiscal year ending March 2026, hit by slumping global steel prices driven by China's excess production and exports and impact from U.S. tariffs.

(Reporting by Yuka Obayashi, Ritsuko Shimizu; Editing by Raju Gopalakrishnan)

((Yuka.Obayashi@thomsonreuters.com; +813-4520-1265;))