Ishin no To (Japan Innovation Party), the second largest opposition party, is on the brink of disintegration once again as a confrontation between its Osaka-based and Tokyo-based members intensified Wednesday.

Osaka Gov. Ichiro Matsui, one of the two party founders and now a special adviser to the party, threatened to quit his position unless party secretary-general Mito Kakizawa resigns immediately.

Matsui told reporters in Osaka that he is ready to submit a letter of resignation Thursday unless Kakizawa steps down. He also claimed Osaka Mayor Toru Hahshimoto, the other party founder and longtime ally of Matsui's, is likewise ready to quit as supreme party adviser.