Sept 25 (Reuters) - U.S. Steel said on Wednesday

an arbitration board had ruled in favour of Nippon Steel's ( NISTF )

$14.9 billion buyout of the company, but that the

United Steelworkers union (USW)disagreed with the decision.

The board, jointly selected by the company and the union to

settle disputes, ruled that U.S. Steel had satisfied each of the

conditions of the successorship clause in its basic labour

agreement with the USW.

"The arbitrators accepted at face-value Nippon Steel's ( NISTF )

statement that it would assume the Basic Labor Agreement," USW

said.

The union said the decision did not change its opposition to

the deal.

In a statement, Nippon Steel ( NISTF ) said: "We remain focused on

forging a productive relationship with the USW, which includes

fulfilling our commitments that go far beyond what is currently

required in the existing BLA,", referring to the basic labour

agreement.

The deal has faced political opposition since it was

signed last December. Democratic presidential candidate Kamala

Harris and her Republican challenger Donald Trump say they

support keeping U.S. Steel as an American-owned company.

Nippon Steel ( NISTF ) agreed to pay a hefty premium to clinch the

deal for U.S. Steel on a bet that it could benefit from U.S.

President Joe Biden's infrastructure spending bill.

Earlier this month, U.S. Steel warned that a failure to

conclude the deal would put thousands of U.S. union jobs at risk

and signalled that it would close some steel mills and

potentially move its headquarters out of the politically

important state of Pennsylvania.

Nippon Steel ( NISTF ) President Tadashi Imai told reporters on

Thursday in Tokyo that the U.S. Committee on Foreign Investment

(CFIUS) had extended its review of the deal until the end of

December, or until after the Nov. 5 presidential elections.

He said the extension was not necessarily a reason to be

overly optimistic and the company continued to seek dialogue

with the USW as it aimed to close the deal by the end of

December.

With regard to Imai's comments on CFIUS, a Nippon Steel ( NISTF )

spokesperson later said: "Due to confidentiality of obligations,

we have requested that this comment be withdrawn."