The government will release the results of the reopened Kake Gakuen probe "as quickly as possible" but will not allow a third party to join the investigation, Chief Cabinet Secretary Yoshihide Suga suggested Monday.

"The investigation at this time is not about any illegal acts but is an additional probe into whether the documents exist or not," Suga told a news conference.

"So I think the education ministry will conduct" the investigation, he said, dismissing suggestions that allowing an independent third party to oversee the process would improve its credibility.