The Finance Ministry admitted Wednesday that it disposed of documents to conceal negotiations with a school operator with ties to the wife of Prime Minister Shinzo Abe before giving it a steep discount in a state property sale.

The latest evidence of a government effort to cover up the murky deal comes less than three months after the ministry admitted to doctoring separate documents to comply with parliamentary remarks by a senior bureaucrat, who stated the ministry had held no price talks with Moritomo Gakuen before the 2016 land sale.

Abe said Wednesday it is "inappropriate to dispose of documents in relation to remarks in the Diet," calling the action "truly regrettable" while reiterating that neither he nor his wife was involved in the price cut.

The documents disposed of were part of records on negotiations between ministry officials and Moritomo Gakuen, which was offered a state-owned plot of land at less than a seventh of the appraisal price.

According to the ministry, officials at the bureau in charge of managing state assets pushed for the documents to be disposed of because they contradicted testimony given by Nobuhisa Sagawa, the head of the bureau at the time.

Sagawa, who has since resigned, had told parliament that there was no collusion in setting the price for the land in Toyonaka, Osaka Prefecture, where Moritomo Gakuen planned to build an elementary school. Akie Abe, the prime minister's wife, served as honorary principal of the elementary school but gave up the post after the controversial land sale came to light in February last year.

Despite Sagawa's remarks, it was later revealed that the Finance Ministry had offered to negotiate a price before the appraisal process was finished. The land was eventually sold for 134 million yen ($1.2 million), after 822 million yen was discounted, ostensibly to pay for the removal of waste buried at the site.

The ministry, which recovered some of the documents from officials who had personally kept copies, on Wednesday released over 900 pages of records from between 2013 and 2016.

(Yasunori Kagoike, former head of Moritomo Gakuen, and his wife Junko)

The records showed ministry officials had been in contact with Akie Abe's then-aide Saeko Tani regarding the sale, as well as the aides of five lawmakers from the prime minister's Liberal Democratic Party.

One record revealed Tani made two inquiries with the Finance Ministry in November 2015 about Moritomo Gakuen's request for a reduction in the rental price for the land. The ministry leased the lot to the school operator before selling it.

Another shows that a Moritomo Gakuen administrator told ministry officials in July 2015 that "Prime Minister Abe, his wife and senior LDP members are aware of the plans to open an elementary school" on the site, an apparent attempt to leverage political influence.

As cronyism allegations against Shinzo Abe have mounted, opposition lawmakers criticized his administration's handling of the matter, with Yuichiro Tamaki, co-head of the Democratic Party for the People, calling on the prime minister to "consider stepping down" to take responsibility.

The ministry on Wednesday released roughly 3,000 pages of the documents it had tampered with, after restoring them to their original state, and plans to publish the results of an internal probe into the matter possibly within the month.

The former head of Moritomo Gakuen, Yasunori Kagoike, 65, is an acquaintance of Akie Abe and has claimed he was given special treatment in the land sale because of their relationship.

Kagoike and his wife Junko, 61, were arrested on July 31, 2017, on unrelated charges including defrauding the central and local governments of 170 million yen in school subsidies, and have been in detention since.

The Osaka District Court on Wednesday decided to allow the couple out on bail, accepting a request from their lawyer after rejecting a previous request in November, the lawyer said.

Prosecutors quickly appealed the decision. Their respective bail of 8 million yen and 7 million yen has not been paid yet.