The Tokyo District Court said Thursday it has rejected a Mongolian bidder's offer to buy out the headquarters and land in downtown Tokyo of a pro-Pyongyang Korean residents' group.

In October, the Mongolian firm, identified as Avar Limited Liability Co., offered the highest bid of ¥5.01 billion to buy the property of the General Association of Korean Residents in Japan (Chongryon). The group acts as North Korea's de facto embassy in Japan in the absence of diplomatic ties between the two nations.

The court said the auction result was invalid as some of the documents submitted by the firm were copies rather than originals. A third round of bidding will be held, court officials said.

Earlier reports said the Ulan Bator address the little-known firm provided did not exist.

In 2012, the court decided to auction Chongryon's headquarters as demanded by the government-backed Resolution and Collection Corp., which is owed about ¥62.7 billion by Chongryon following the collapse of financial institutions in Japan for pro-North Korean residents.

In the first round, held last March, Saifuku Temple in Kagoshima Prefecture won the bidding to acquire Chongryon's 10-story head office with two basement floors and its 2,387-sq.-meter tract of land in central Tokyo's Chiyoda Ward.

But the temple, whose chief priest, Ekan Ikeguchi, is known to maintain close ties with senior officials of the North Korean government and Chongryon, failed to pay the bid price by the deadline and was eliminated in the second round of auction.

Avar Limited Liability was one of the two bidders that filed bids in the second round in October, court officials said.

Avar head Chuvaamed Erdenebat said at the time the bid was a purely business decision.