TOKYO (Kyodo) -- Honda Motor Co. and Nissan Motor Co. said Friday they will unveil the details of their merger plan in mid-February, having originally announced they would do so by the end of this month.

Honda and Nissan, Japan's second- and third-largest carmakers by volume, said they are still discussing the finer points of the merger.

The two carmakers said at a press conference last month that they had agreed to begin talks on merging under a holding company in 2026 and that each company would operate under its own brand within the holding company.

Honda chief executive Toshihiro Mibe said at the press conference that Honda wanted struggling Nissan to make steady progress in restructuring as a precondition for the merger.

Honda has been urging Nissan to strengthen its restructuring efforts, according to sources close to the matter.

In November, Nissan said it would cut 9,000 jobs worldwide and reduce its global production capacity by 20 percent after it reported a more than 90 percent drop in net profit in the April-September period.

As part of the overhaul measures, Nissan planned to offer early retirement programs to employees at its three U.S. plants while reducing its workforce in Thailand, the sources said.

But Honda remains unconvinced, calling for more drastic measures to ensure its successful turnaround, they said.

Mitsubishi Motors Corp., a partner of Nissan, had been considering joining the merger but is now leaning toward not participating in the holding company, according to other sources.

The automaker hopes to maintain its status as a listed company while exploring collaboration with Honda and Nissan without joining the merger, the sources said, adding that Mitsubishi Motors is expected to make a final decision in mid-February or later.