Japanese Olympic Committee President Yamashita Yasuhiro has expressed regret over recent arrests of a former Tokyo Olympics executive and three others in connection with suspected bid-rigging for test events.

Yamashita told reporters on Tuesday that it is true that the arrests have tarnished the image of sports and the Olympics. He also said he is taking the scandal very seriously and closely watching related developments.

A former deputy director of the Tokyo Olympics and Paralympics Organizing Committee's operations bureau and three others were arrested on suspicion of violating Japan's Anti-Monopoly Act. They are suspected of involvement in rigging bids for Games test events.

Asked about the scandal's possible impact on Japan's bid for the 2030 Winter Games, Yamashita said the bid is getting increasingly difficult. The northern Japanese city of Sapporo and the JOC are seeking to host the event.

Yamashita said the JOC will take time to reorganize its campaign to restore trust and gather momentum for the Games in cooperation with the Sapporo city government.