Four major parties in the Tokyo Metropolitan Assembly agreed Monday to set up a powerful committee to look into the issues dogging the Tsukiji fish market relocation plan and possibly summon former Gov. Shintaro Ishihara as a sworn witness.

Ishihara was governor when the metropolitan government decided to buy land in the nearby Toyosu area in Koto Ward to host the famous but aging fish market in Chuo Ward.

Gov. Yuriko Koike has put the move on hold amid pollution at the new site, which was hosted a gas production plant, and has publicly called on Ishihara to clarify his role in the purchase.