Of the 22 people recently banned from re-entering Japan after visiting North Korea, one is an authority in rocket engine development with a doctorate from the University of Tokyo, a government source said Saturday.
The expert has ties to a North Korean company suspected of being involved in developing missile engines, according to the public security source.
Japan, South Korea, the United States and the U.N. Security Council all recently approved additional sanctions to punish North Korea for conducting a fourth nuclear test in January and the launch last month of a rocket, widely seen as a pretext for testing long-range ballistic missile technology.
The 22 people on Japan's own newly complied no reentry list also include officials from the pro-Pyongyang General Association of Korean Residents in Japan, commonly known as Chongryon, and five members of an association of Korean scientists and engineers living in Japan, according to other sources.
The five association members include a researcher at the atomic energy research institute of a national university in western Japan, according to the public security source.
An investigation into the illegal import of food from North Korea by a son of Chongryon Chairman Ho Jong Man found that Pyongyang appears to have sought access to advance technologies through Koreans living in Japan, according to police sources.