Pakistan severs diplomatic relations with India, initiating the Indo-Pakistani War of 1971.

The Indo-Pakistani war of 1971, also known as the third Indo-Pakistani war, was a military confrontation between India and Pakistan that occurred during the Bangladesh Liberation War in East Pakistan from 3 December 1971 until the Pakistani capitulation in Dhaka on 16 December 1971. The war began with Pakistan's Operation Chengiz Khan, consisting of preemptive aerial strikes on eight Indian air stations. The strikes led to India declaring war on Pakistan, marking their entry into the war for East Pakistan's independence, on the side of Bengali nationalist forces. India's entry expanded the existing conflict with Indian and Pakistani forces engaging on both the eastern and western fronts.