The launch of Operation Chengiz Khan by West Pakistan on North India finally drew India into the Bangladesh conflict and a joint command structure was established between the Bangladeshi and Indian forces . Three corps of the Indian Armed Forces were supported by three brigades of the Mukti Bahini and the Bengali guerrilla army . The Mukti Bahini and its supporters guided the Indian army and provided them with information about Pakistani troop movements . The Indian and Mukti Bahini greatly outnumbered the three Pakistani army divisions of East Pakistan . The Battle of Sylhet , the Battle of Garibpur , the Battle of Boyra , the Battle of Hilli and the Battle of Kushtia were major joint engagements for the Bangladeshi and Indian forces , who swiftly captured surrounding land by selectively engaging or bypassing heavily defended strongholds . For example , the Meghna Heli Bridge airlifted Bangladeshi and Indian forces from Brahmanbaria to Narsingdi over Pakistani defences in Ashuganj . The cities of Jessore , Mymensingh , Sylhet , Kushtia , Noakhali and Maulvi Bazar quickly fell to the Mukti Bahini-Indian joint forces . In Dhaka , the Pakistan Army and its supporting militias began the mass murder of Bengali intellectuals and professionals in a final attempt to eliminate the Bengali intelligentsia . Historian Yasmin Saikia writes that the Mukti-Bahini , Indian forces , the Pakistani Army , and pro-Pakistani militias looted , raped , and killed civilians in East Pakistan . The Mukti Bahini liberated most of the Dhaka District by mid-December . In Western Pakistan , Indian forces advanced deep into Pakistani territory as the Port of Karachi was subjected to a naval blockade by the Indian Navy . Pakistani generals surrendered to the Mukti Bahini-Indian forces in Dhaka on 16 December 1971
mass murder of Bengali intellectuals
1971 killing of Bengali intellectuals
Mukti Bahini