A potential summit between Japanese Prime Minister Yoshihide Suga and South Korean President Moon Jae-in later this week in Tokyo has been thrown into doubt after a Japanese diplomat made inappropriate comments about the South Korean leader.

Japan's Yomiuri newspaper reported Monday the two leaders would meet Friday in the Japanese capital to coincide with President Moon's attendance at the opening ceremonies of the Tokyo Olympics.

But a statement released by South Korea's Presidential Blue House, Moon's official residence and office, suggested the meeting was in doubt due to an "obstacle" in the final discussions, an apparent reference to a comment by a high-level envoy attached to the Japanese embassy in Seoul.

The envoy, identified by South Korea's Yonhap news agency as Hirohisa Soma, the embassy's deputy chief of mission, reportedly compared Moon's efforts to improve ties with Seoul to sexual self-gratification during an interview with a local reporter.

Relations between the East Asian neighbors have grown acrimonious in recent years due to South Korea's lingering bitterness over Japan's brutal colonial occupation of the Korean peninsula from 1910-45. Scores of Korean women were forced to work in Japanese military brothels during the war as "comfort women," while thousands of other Koreans were forced to work in Japanese factories during that time.

Several surviving "comfort women" have filed lawsuits in South Korea seeking compensation from Japan for their ordeal, with mixed results. Tokyo maintains it had settled the issue under a 1965 treaty that normalized bilateral relations with Seoul that included $800 million in reparations, as well as a separate deal reached in 2015.

This report includes information from Reuters.