It was during O'Dwyer's tenure as Lieutenant Governor of Punjab that the Jallianwala Bagh massacre occurred in Amritsar, on 13 April 1919, three days after the onset of the riots. According to British estimates, 379 unarmed civilians were killed by Gurkha troops under the command of Brigadier General Reginald Dyer. Some estimates are greater, with more than 1500 casualties. O'Dwyer was informed of the event at 3 am the following day. When he received Dyer's initial report, O'Dwyer gave permission to General Beynon to send a telegram to Dyer which stated "your action correct and the lieutenant-governor approves".