Terrorists tend to coordinate multiple raids which, combined with diversionary attacks are designed to divert the attention of the security forces, causing them to take a longer time to respond. This in turn enables the terrorists to cause more casualties at their primary target. It is important to efficiently reallocate the available security forces to meet these terrorist attacks, especially when the available resources are limited. In this paper we proposed two game theory-based models for the reallocation of security forces for the purpose of countering both primary and diversionary attacks in an urban environment. The first model is used each target and the ldquoattack on hidden-object gamerdquo in which one analyzes the interaction behavior between the security force commander and the terrorists within a zero-sum game. The probability of a primary attack to this target is derived from the mixed strategy Nash equilibrium. The second model uses all these probabilities to compute the Shapley value for each target, in terms of the majority of all probabilities for primary attacks. The Shapley values are then used to create a reallocated set of the limited security forces. Experimental results show the approach proposed in this study is more efficient than the traditional method for dealing with ever more likely gunshot events.