Complex sentence: At that time, the Naga rebels and the Indian army were constantly at "war" and hence the militants considered any "Indian" as a "spy" and they warned villagers not to give shelter and ration to Thakkar.
Split into simpler sentences: At that time, the Naga rebels and the Indian army were constantly at "war" and so any "Indian" was considered as a "spy" by the militants. Militants warned villagers not to give shelter and ration to Thakkar.