Mito Kakizawa, state minister of justice, resigned Tuesday after admitting his involvement in election campaign misconduct in the spring, further weakening Prime Minister Fumio Kishida’s already precarious standing with the public.

On Tuesday, the Asahi Shimbun reported on Kakizawa’s involvement in the alleged online posting of a paid campaign advertisement in April, when Yayoi Kimura was elected as mayor of Tokyo's Koto Ward.

According to media reports, Kakizawa — a Liberal Democratic Party lawmaker representing the capital’s Koto Ward in the Lower House — admitted that he had recommended Yayoi’s team make use of paid YouTube advertising during her campaign, without knowing such an action would constitute a violation of the election law. The case is currently being investigated by the Tokyo prosecutor’s office.