This paper addresses assignment of defensive weapons against a number of incoming targets, particularly when the targets are aiming to a relatively small local area in a high-density manner. The major issue this work tries to deal with is potential interference between the defensive weapons due to short distance between them and/or inclusion within seeker sensing range. The problem is formulated in a time-dependent static weapon-target assignment with operational and interference constraints; a greedy algorithm that features approximate prediction of potential interference. A numerical case study on assignment of defensive interceptor against incoming ballistic objects is presented to demonstrate the efficacy of the proposed method.