I am wondering if there is any international organization regulating such things.
Possibly countries do not need to tell anything about their spy satellites, but should tell about their commercial satellites.
No, they don't need to, but the UN requests that a country report their spacecraft.
Personally, I suspect that many spy satellites are reported and tracked, except that the true nature of their function is not fully disclosed.
The Registration Convention provides that the launching State should furnish to the United Nations, as soon as practicable, the following information concerning each space object:
- Name of launching State;
- An appropriate designator of the space object or its registration number;
- Date and territory or location of launch;
- Basic orbital parameters, including:
- Nodal period (the time between two successive northbound crossings of the equator - usually in minutes);
- Inclination (inclination of the orbit - polar orbit is 90 degrees and equatorial orbit is 0 degrees);
- Apogee (highest altitude above the Earths surface - in kilometres);
- Perigee; (lowest altitude above the Earths surface - in kilometres);
- General funtion of the space object.
Source: https://web.archive.org/web/20080212011440/http://www.unoosa.org/oosa/en/SORegister/index.html