It all started with Operation Searchlight, a planned military pacification carried out by the Pakistan Army started on 25 March, 1971 to curb the Bengali nationalist movement by taking control of the major cities on March 26, and then eliminating all opposition, political or military, within one month. Before the beginning of the operation, all foreign journalists were systematically deported from Bangladesh. The main phase of Operation Searchlight ended with the fall of the last major town in Bengali hands in mid May.
According to New York Times (3/28/71) 10,000 people were killed; New York Times (3/29/71) 5,000-7,000 people were killed in Dhaka; The Sydney Morning Herald (3/29/71) 10,000 – 100,000 were killed; New York Times (4/1/71) 35,000 were killed in Dhaka during operation searchlight.
The operation also began the 1971 Bangladesh atrocities. These systematic killings served only to enrage the Bengalis, which ultimately resulted in the secession of East Pakistan later in December, 1971. The international media and reference books in English have published casualty figures which vary greatly; 200,000–3,000,000 for Bangladesh as a whole.
There is only one word for this: Genocide.
Genocide in Bangladesh, 1971