"The Indian move violated China's territorial sovereignty. We strongly express our dissatisfaction and opposition," Xinhua news agency cited the deputy director of the army's western theatre combat bureau, Zhang Shuili, as claiming.
Zhang, however, could not give details about when or where the incident happened.
Chinese border troops "took a professional and responsible attitude" and carried out identification verification of the device, Zhang claimed.
Army chief Bipin Rawat had said in September that India could not afford to be complacent and must be prepared for war.