We present a swarm of autonomous Unmanned Aerial Vehicles (UAVs) capable of persistent surveillance as well as engagement of the hostile targets identified on the ground. That is, for a given area of interest, that might be hostile, we design a capability of monitoring ground targets by the swarm of autonomous armed UAVs in persistent way that will be capable of engaging these targets if necessary. The UAVs decide by themselves when and how to come back to the maintenance site(s) in order to be recharged of refueled. A single Operating Control Unit (OCU) is sufficient to integrate with such a swarm of UAVs. Its role is mainly focused on sending high level commands, some of which might overwrite the UAVs autonomous intention. For example, a commander might request through OCU engagement of target(s), look for specific target(s), or immediate return of some UAVs to the maintenance sites. Since UAVs are autonomous then the communication links from OCU to UAVs do not need to be continuously maintained.