In this paper we present an integrated system for intelligent video surveillance, control and alarm generation in security applications related to protection of public buildings (e.g. various financial institutions). By using only two networked cameras, video information is collected, dispatched via network and processed on-line with a group of integrated image processing algorithms able to detect humans in motion, track their motion, and check the visibility of their faces while entering the building. In addition, the developed system counts people's traffic and keeps the record of a number of people in the protected area. The integration of given algorithms is made in order to raise the reliability of the threat recognition. The emphasis is on the fast detection of the invisible (masked) face of the approaching person. Based on the outputs of the algorithms, either alarm generation or adequate control actions may take place.