Hostile relations in the past between India and Pakistan added to India's decision to intervene in Pakistan's civil war. As a result, the Indian government decided to support the creation of a separate state for ethnic Bengalis by supporting the Mukti Bahini. RAW helped to organise, train and arm these insurgents. Consequently, the Mukti Bahini succeeded in harassing Pakistani military in East Pakistan, thus creating conditions conducive for a full-scale Indian military intervention in early December. The Indian military and Mukti Bahini had the edge with better weaponry, complete air and naval supremacy and support from most locals. The Pakistani army fought ferociously and many were killed. With air supremacy achieved in the eastern theatre and the rapid advance of the Allied Forces of Bangladesh and India, Pakistan surrendered in Dacca on 16 December 1971.