Under what condition is FPCON Delta implemented?

FPCON Delta is specifically implemented in response to a serious threat level, particularly in the immediate area where a terrorist attack has just occurred. This condition reflects a heightened state of security due to an imminent threat or actual attack, where the objective is to ensure the safety and security of personnel and assets. The emphasis is on immediate and stringent security measures to mitigate any further threats following an attack.

In contrast, other options describe situations that do not warrant the extreme measures of FPCON Delta. For instance, heightened security due to a potential threat would fall under an increased readiness status rather than a direct response to an attack. Similarly, responding to a non-specific threat doesn't necessitate the drastic security actions associated with FPCON Delta. Lastly, the normal readiness status under peacetime conditions indicates a standard level of security that does not reflect the urgent and reactive nature of FPCON Delta.