Nippon Steel Corp., the world's second-largest steelmaker, said Tuesday no "concrete" decision had been made about expanding cooperation with bigger rival Arcelor Mittal.

Nippon Steel in July 2004 formed a venture with Arcelor and Baosteel Group Corp. to make sheet metal for autos in Shanghai. Mittal Steel Co.'s $38.3 billion purchase of Arcelor SA last year left the merged company to renegotiate where it may use Nippon Steel's production technology.

"Nothing concrete has been decided by Nippon Steel with Arcelor Mittal," said Masato Suzuki, a spokesman for the Tokyo-based steelmaker, responding to a report in the Nikkei newspaper Tuesday morning saying the companies are likely to agree by next month on extending their cooperation.

Nippon Steel, which makes 29 percent as much of the alloy as its bigger rival, last year took steps to fend off takeover attempts and has said it will expand alliances with rivals to meet rising demand without acquiring other companies.

Nippon Steel President Akio Mimura will meet with Arcelor Mittal Chief Executive Officer Lakshmi Mittal next month in New York, the Nikkei reported. The companies may agree to expand automotive-steel partnerships in China and North America, the newspaper said.

"We can't comment on the schedule of executives," said Nippon Steel's Suzuki. A telephone message left at Arcelor Mittal was not immediately returned.

Mittal said June 13 he doesn't rule out "large" acquisitions.

Nippon Steel produced 34 million tons of the metal in 2006, compared with Arcelor Mittal's 118 million tons, according to London's Iron and Steel Statistics Bureau.

Nippon Steel built three new domestic production lines for galvanized steel last year.

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