Ground Self-Defense Force spies have secretly gathered intelligence abroad since the Cold War era without informing the prime minister or defense minister, a practice considered deviating from civilian control, former senior defense officials said Wednesday.

A special unit of the Ground Staff Office has set up bases in Russia, China, South Korea and Poland, if not elsewhere, and several dozen GSDF members of the team have engaged in intelligence activities overseas without a legal basis and by assuming false identities, according to the officials.

The prime minister acts as the commander-in-chief of the Self-Defense Forces and the defense minister supervises the forces. The Diet also has a say in some SDF activities.