Shintaro Ishihara, co-head of Nippon Ishin no Kai (Japan Restoration Party), made a gaffe Friday regarding the status of one of the Japanese nationals abducted by North Korea decades ago, calling her a "mistress."

Referring to Megumi Yokota, who was abducted by North Korean agents in 1977 at age 13, as a "Japanese beauty," Ishihara said at a stump speech in Yokohama that she must have "been forced into marrying and giving birth to a child" and "become a mistress of someone in a high position."

Ishihara's comments during the official campaigning for the July 21 Upper House election will outrage Japanese abductees' kin and supporters and stir criticism for his insensitivity to the feelings of the parents of Yokota, a symbol of the abductee issue.

Nippon Ishin was already under fire worldwide and especially in Asia and the United States for earlier remarks made by the party's other co-leader, Toru Hashimoto, also Osaka mayor, attempting to justify Japan's sex slave system.

Speaking to reporters in Osaka Prefecture, Nippon Ishin Secretary General and Osaka Gov. Ichiro Matsui tried to downplay the latest contentious comments, saying he believed Ishihara was "talking about the need to help people who have been deprived of freedom and living a hard life."

North Korea admitted in 2002 to having abducted or lured Japanese nationals including Yokota, who it claimed had committed suicide in 1994. In 2004, it handed over to Japan cremated remains it claimed were Yokota's. However, DNA tests conducted in Japan proved the claim to be untrue.

Ishihara also said, "Based on circumstantial evidence, North Korea abducted more than 300 people."