Mukti Bahini used Guerrilla warfare tactics to fight against the Pakistan Army . India provided economic , military and diplomatic support to the Mukti Bahini , leading West Pakistan to launch Operation Chengiz Khan , a preemptive attack on the western border of India which started the Indo-Pakistani War of 1971 . The operation also precipitated the 1971 Bangladesh genocide and caused roughly 10 million refugees to flee to India . Essentially Bengali intelligentsia , academics and Hindus were targeted for the harshest treatment , with significant indiscriminate killing taking place . These systematic killings enraged the Bengalis , who declared independence from Pakistan , to achieve the new state of Bangladesh
1971 Bangladesh genocide
1971 Bangladesh genocide
Crack Platoon