Bangladesh Liberation War initially commenced in the form of resistance movement as the Pakistan Army cracked down on 25 March 1971 primarily at Dhaka and subsequently extending it to the entire of Bangladesh. Gradually, the Bangladesh Forces organised small groups of guerrilla fighters who followed 'hit and run' tactics. As a third stage in the war, the Bengali military personnel who were members of Pakistan Army, Navy and Air Force deserted their respective units to join Bangladesh Forces and organised them into regular units across the border of Indian territory primarily as Land Force. A small group of Naval Commandos also opened the Naval wing and a few Pilots and Airmen formed the Air Wing.