A former member of a special Ground Staff Office unit has told Kyodo News about intelligence activities long conducted without the knowledge of the prime minister or defense minister, including paying several million yen to collaborators and sending a spy to North Korea.

The unit's very existence has been kept secret, even within the Ground Self-Defense Force, the source said. Defense Minister Itsunori Onodera on Wednesday denied the unit exists.

The source described enrolling in a psychological warfare and security course at a GSDF school in Kodaira, western Tokyo, under orders from a superior.