May 2 (Reuters) - The U.S. Department of Justice is

seeking more details and documentary materials as part of an

antitrust review of Nippon Steel's ( NISTF ) proposed $15 billion

takeover of U.S. Steel, the American firm said on Thursday.

Commonly known as a "second request," it can mark the start

of a lengthy legal process from which few mergers emerge

successful.

The DoJ's request comes after the Japanese firm's proposed

bid drew sharp criticism in the U.S., including from President

Joe Biden, who said the asset should be domestically owned.

However, an overwhelming majority of U.S. Steel shareholders

voted in favor of the deal in April.

Despite fears of layoffs, Japan's largest steelmaker has

pledged no job cuts as a result of the merger and has said it

will move its own U.S. headquarters to Pittsburgh where U.S.

Steel is based.

The acquisition of U.S. Steel will help Nippon, the world's

fourth-largest steel maker, move toward 100 million metric tons

of global crude steel capacity.

U.S. Steel now expects that the merger will be completed in

the second half of 2024, it said on Thursday, as its prior

deadline of second to third quarter of 2024 nears.