Osaka Gov. Ichiro Matsui and three current and former Osaka Diet members were named by Moritomo Gakuen head Yasunori Kagoike on Thursday as being involved in a shady land deal that has shaken the administration of Prime Minister Shinzo Abe and Osaka's relationship with the ruling coalition.

With Tuesday's revelations, the scandal looks set to pick up steam as opposition parties attempt to confirm Kagoike's claims and increase pressure on Abe to summon those in Osaka named, including Matsui, other members of his party and Osaka bureaucrats involved with Moritomo, to appear before the Diet.

In addition, there are calls in Osaka and elsewhere to have the prime minister's wife, Akie, testify about Kagoike's statement that he personally received a ¥1 million donation from her in an envelope. Kagoike indicated to the Foreign Correspondents' Club of Japan on Thursday evening that other employees at the school knew about the donation, which the prime minister has denied and about which his wife had said she has no recollection.