Localization and identification of nuclear and radiological material are main issues in case of nuclear accident or terrorist attack. In these cases, the use of a unmanned aerial vehicle would be highly recommended in order to preserve the safety of the human operators. For this purpose, we have integrated a compact, light, low power operating, CZT-based gamma ray detector on a commercially available UAV. The system allows exploration of potentially dangerous areas without a close exposure of the human operator. The operator is able to provide motion commands to the UAV while receiving force feedback from a 3DOF haptic interface. Force feedback provides an attractive basin around the location of the most intense detected radiation. A field experiment has been carried out and a 192 Ir nuclear source has been localized and identified exploiting the novel teleoperation system.