U.S.-based Fortress's 4,000 yen-per-share offer was originally set to end on Thursday.

Fortress had emerged in August as a white knight for Unizo with a 137 billion yen bid when the hotelier was the target of H.I.S.. But Unizo later withdrew its support.

On Tuesday, Blackstone Group ratcheted up its pursuit of Unizo by launching a 5,000 yen-per-share tender offer.

(Reporting by Junko Fujita and Chris Gallagher; Editing by Muralikumar Anantharaman)