The Indo-Pakistani war of 1965, also known as the second Indo–Pakistani war, was an armed conflict between Pakistan and India that took place from August 1965 to September 1965. The conflict began following Pakistan's unsuccessful Operation Gibraltar, which was designed to infiltrate forces into Jammu and Kashmir to precipitate an insurgency against Indian rule. The seventeen day war caused thousands of casualties on both sides and witnessed the largest engagement of armoured vehicles and the largest tank battle since World War II. Hostilities between the two countries ended after a ceasefire was declared through UNSC Resolution 211 following a diplomatic intervention by the Soviet Union and the United States, and the subsequent issuance of the Tashkent Declaration. Much of the war was fought by the countries' land forces in Kashmir and along the border between India and Pakistan. This war saw the largest amassing of troops in Kashmir since the Partition of India in 1947, a number that was overshadowed only during the 2001–2002 military standoff between India and Pakistan. Most of the battles were fought by opposing infantry and armoured units, with substantial backing from air forces, and naval operations.