The officials in charge of building a new National Stadium for the 2020 Olympics, including sports minister Hakubun Shimomura, failed to develop an organizational structure capable of handling such a complex project, a third-party panel probing the fiasco concluded Thursday.

In a 60-page report submitted to the minister, the six-member panel, led by University of Tokyo professor emeritus Noboru Kashiwagi, said Shimomura, senior bureaucrat Shinichi Yamanaka and Japan Sports Council President Ichiro Kono were ultimately responsible for the scrapping of the costly design proposed by Iraqi-British architect Zaha Hadid.

Hadid's design, which featured extravagant "keel arches" to form the backbone of the roof, resulted in ballooning costs. Amid the public outcry, Prime Minister Shinzo Abe announced in July that the plan would be scrapped, and the JSC is now selecting architects for a new plan.