In this paper, the research project named "networked robotic system for disaster mitigation" is introduced. The project aims to develop key technologies for multiple robots to be teleoperated through a wireless communication network, which includes a satellite communication link, for surveillance tasks at a disaster site. The robotic system consists of a large-scale outdoor robot and a group of smaller indoor robots. The large-scale robot will serve as a carrier for the smaller robots which are deployed inside a partly-collapsed building. A three-dimensional range sensor and an omnidirectional camera are used as tools to ease the teleoperation for the human operator. This paper presents the mission scenario and the development status of the proposed networked multi-robotic system. The results of the performance tests are also reported.