Intelligence should aim at predicting the development of a terrorist threat or supplying warning of the possibility or probability of such a threat. Correct assessment of the threat is important, since it is a major factor in the authorities' decisions regarding what measures to take. If, for reasons beyond the control of intelligence, the terrorist threat develops despite earlier prediction, intelligence must help to combat the threat. This requires a clear, distinct, delineation of responsibility among the various intelligence services in the concerned State. Some possible sources of intelligence are the media, prisoners, detainees, visual intelligence, informants, listening devices, and sophisticated communications intelligence. Intelligence must be an organic part of the command post that is responsible for the overall direction of a counterterrorist operation. Psychological warfare, aiming at the terrorists' minds, should also be an integral part of the intelligence operation. Intelligence should also be used selectively to inform the general public about terrorist tactics and actions that should be taken to counter them.