WASHINGTON (Reuters) -U.S. President Donald Trump said on Thursday the United States had a "golden share" in U.S. Steel as part of a deal for Nippon Steel ( NISTF ) to buy the iconic American company.

It was not immediately clear what structural element of the deal Trump was referring to, but he said the share meant that Americans would have a 51% share in ownership of the steelmaker.

"We have a 'golden share', which I control, the president controls," he told reporters at the White House. "If that gives you total control, it's 51% ownership by Americans."

Nippon Steel ( NISTF ) and U.S. Steel did not respond to requests for comment.

On Friday, a Nippon Steel ( NISTF ) executive told the Nikkei business daily the acquisition of U.S. Steel required "a degree of management freedom" to go ahead, in a sign that last-minute discussions continue regarding the deal structure.

"The idea to contribute to the revival of U.S. manufacturing (through Nippon Steel's ( NISTF ) investment) is in line with the U.S. administration's policy," Nikkei quoted the unidentified executive as saying.

"Without a degree of management freedom, it may not be possible to reach an agreement with the U.S. government."

At a rally in Pennsylvania on May 30, Trump lauded a deal between the companies, calling Nippon Steel ( NISTF ) 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.

Nippon Steel ( NISTF ) and the Trump administration asked a U.S. appeals court on June 5 for an eight-day extension of a pause in litigation, to give them more time to reach a deal for the Japanese firm to buy U.S. Steel for $14.9 billion.

Nippon Steel ( NISTF ) shares closed down 1.48% in Tokyo on Friday, outstripping a fall of 0.89% in the benchmark Nikkei.