WASHINGTON/MEXICO CITY June 4 (Reuters) - Mexico's

antitrust watchdog is expected to renew its approval of Nippon

Steel's ( NISTF ) fraught $14.9-billion bid for U.S. Steel as soon as

Thursday, according to three people familiar with the matter,

removing one of the last remaining hurdles to the tie-up.

Cofece, as the regulator is known, gave the merger a green

light previously, the people said, declining to be named as the

matter was not public. Mexican approval of the proposed

acquisition, first announced in December 2023, has since expired

and must be renewed for the merger to proceed.

Cofece did not immediately respond to requests for comment.

U.S. Steel and Nippon Steel ( NISTF ) declined to comment.

The news, which has not been previously reported, comes as

investors wait anxiously for President Donald Trump to give

final approval of an agreement to assuage any U.S. national

security concerns.

Trump technically has until Thursday to sign it.

The tie-up faced obstacles from the start, with both former

President Joe Biden and Trump asserting last year that U.S.

Steel should remain U.S.-owned, as they sought to woo voters

ahead of the presidential election in Pennsylvania, where the

company is headquartered.

Biden blocked the deal in January on national security

grounds, prompting lawsuits by the companies, which argued the

national security review they received was biased. The Biden

White House disputed the charge.

The steel companies saw a new opportunity in the Trump

administration, which began on January 20 and opened a fresh

45-day national security review into the proposed merger in

April.

But Trump's public comments, ranging from welcoming a simple

"investment" in U.S. Steel by the Japanese firm to floating a

minority stake for Nippon Steel ( NISTF ), spurred confusion.

On Friday, at a rally in Pennsylvania, Trump lauded an

agreement between the companies and said Nippon Steel ( NISTF ) would make

a "great partner" for U.S. Steel. But he later told reporters

the deal still lacked his final approval, leaving unresolved

whether he would allow Nippon Steel ( NISTF ) to take ownership.