Unizo was little known until it became a target for a

hostile bid by travel agent H.I.S. Co in July, but has

since attracted attention from top global funds looking to buy into Japan's property market on the cheap.

Blackstone had told Unizo it would launch a tender offer or explore other options if Unizo did not agree to its offer of 5,000 yen a share, valuing the company at 171.1 billion yen ($1.6 billion) by Wednesday.

"Blackstone has not received Unizo's consent and entry into an agreement between Blackstone and Unizo with respect to the Blackstone offer," the U.S. buyout fund said in a statement.

"Accordingly, Blackstone is currently assessing all available options and remains prepared to engage in further discussions with Unizo," said Blackstone, adding it would issue another statement on Nov 18.

Unizo had originally supported SoftBank Group-backed Fortress Investment Group, which in August offered a white-knight bid of 4,000 yen a share. But it later withdrew its support for Fortress bid, which values Unizo at 137 billion yen ($1.3 billion) and is due to run until Nov. 11.

Unizo shares closed at 5,090 yen on Thursday.

(Reporting by Junko Fujita; Editing by Edmund Blair and Alexander Smith)