Yorihisa Matsuno, head of Ishin no To (Japan Innovation Party), has sacked three of the party's four top executives, a move likely to accelerate the unfolding disintegration process of the nation's second-largest opposition force.

Among the three to get the ax Tuesday were Nobuyuki Baba, Ishin's Diet affairs chief from Osaka, and Executive Council Chairman Toranosuke Katayama, who also serves as the head of the party's Upper House caucus.

The two had expressed their intention to leave the party soon and join Osaka Ishin no Kai, a local party led by Osaka Mayor Toru Hashimoto.