In this paper, a newly initiated project of networked robotic system for disaster mitigation is introduced. In this project, multiple robots are coordinately operated through ad-hoc wireless communication network, including satellite-based IP communication link, for surveillance tasks at a disaster site. The robot system consists of a large-scale outdoor robot to serve as a carrier of small robots and a fleet of small robots to be deployed at a specific spot such as an inside of a building complex. A combination of a laser range scanner and an omni-directional camera is used to acquire high resolution 3D geometry data and rendering images. Those data and images are displayed using Mixed Reality (MR) technology at a remote site to provide an overall picture for operation managers with high fidelity. This paper presents our initial experiments using a robot test bed with an emphasis on remote operation over rough terrain and for acquisition of high resolution 3D geometry data and telepresence using MR technology.