The effects of terrorist and piracy activities, or generally speaking activities of intelligent opponents can have a large impact on the socio-economic and military well-fare. To counter these increasing, multiple threats, security measures/forces should be deployed to surveil and patrol assigned areas to protect valuable objects and critical infrastructure (e.g. harbours, airports, merchant ships and routes). However, current OR models do not always adequately take into account the complexity of these kind of military operations and the scarcity of resources. Therefore, we are facing the challenge to develop adequate models and methods for the assessment of deployment of scarce security forces in an efficient and effective way given multiple, responsive and adaptive threats, also taking into consideration new technological developments. The key challenge to be tackled in this PhD research is: How to optimally deploy security forces to protect critical infrastructures given limited resources and taking into account multiple adversaries and their intelligent responses?