South Korean prosecutors detained on Tuesday the country's former ambassador to Japan and former chief of the National Intelligence Service over allegations that his agency made illegal payments to aides of then-President Park Geun-hye.

Lee Byung-kee was detained by investigative authorities in Seoul on suspicion that the agency illegally paid 4 billion won ($3.57 million) to the aides during his term, according to the Yonhap news agency. He had been under investigation since Monday.

In Tokyo, Foreign Minister Taro Kono said at a news conference that the detention of Lee, South Korea's main architect of a "comfort women" deal with Japan, would not affect bilateral ties.