India and Pakistan have had testy relations at best since independence. Some key dates that helped define the South Asian nations:
August 1947 - Britain ends its colonial rule over the Indian subcontinent, which becomes two independent nations — Hindu-majority, but secularly governed India and the Islamic republic of Pakistan. The division, widely known as Partition, sparks massive rioting that kills up to 1 million, while another 15 million flee their homes in one of the world's largest human migrations.
October 1947 - The two young nations begin a war over control of Kashmir, a Muslim-majority kingdom ruled by a Hindu maharaja. A U.N.-brokered cease-fire ends the war in a year with Kashmir divided between them.
January 1949 - India and Pakistan agree to a U.N. Security Council resolution calling for a referendum in which Kashmiris would determine their future; the vote never takes place.
September 1960 - India and Pakistan sign a World Bank-brokered Indus Water Treaty governing three rivers. It is the only India-Pakistan treaty that has held.
August 1965 - A second war begins over Kashmir, ending a month later in another U.N.-mandated ceasefire.
December 1971 - A third war is fought, this time as India supports secessionists in East Pakistan. The war ends with the creation of Bangladesh.
July 1972 - The countries' prime ministers sign an accord for the return of tens of thousands of Pakistani prisoners of war.
May 1974 - India conducts a nuclear test, becoming the first nation to do so that's not a permanent U.N. Security Council member.
December 1989 - Armed resistance to Indian rule in Kashmir begins. India accuses Pakistan of giving weapons and training to the fighters. Pakistan says it offers only "moral and diplomatic" support.
May 1998 - India detonates five nuclear devices in tests. Pakistan detonates six. Both are slapped with international sanctions.
February 1999 - Indian Prime Minister Atal Bihari Vajpayee rides a bus to the Pakistani city of Lahore to meet with Pakistan counterpart, Nawaz Sharif, and sign a major peace accord.
May 1999 - Conflict erupts in Kargil as Pakistani forces and Kashmiri fighters occupy Himalayan peaks. India launches air and ground strikes. The U.S. brokers peace.
May 2001 - Vajpayee and Pakistan's President Pervez Musharraf meet in the Indian city of Agra, but reach no agreements.
October 2001 - Insurgents attack the legislature building in Indian-controlled Kashmir, killing 38 people.
December 2001 - Gunmen attack India's Parliament, killing 14. India blames militant groups Lashkar-e-Taiba and Jaish-e-Muhammad, and deploys troops to its western frontier with Pakistan. The standoff ends in October 2002 after international mediation.
January 2004 - Musharraf and Vajpayee hold talks, launching bilateral negotiations to settle outstanding issues.
February 2007 - A train service between India and Pakistan, the Samjhauta Express, is bombed in northern India, killing 68.
October 2008 - India and Pakistan open a trade route across divided Kashmir for the first time in six decades.
November 2008 - Gunmen attack Mumbai, killing 166 people. India blames a Pakistan-based militant group.
May 2014 - India's new Prime Minister Narendra Modi invites Pakistani counterpart Nawaz Sharif to New Delhi for his inauguration.
December 2015 - Modi makes a surprise visit to the Pakistani city of Lahore on Sharif's birthday and the wedding of his granddaughter.
January 2016 - Six gunmen attack an Indian air force base in the northern town of Pathankot, killing seven soldiers in a battle that lasted nearly four days.
July 2016 - Indian soldiers kill Kashmiri rebel leader Burhan Wani, sparking months of anti-India protests and deadly clashes in the region.
September 2016 - Suspected rebels sneak into an Indian army base in Kashmir and kill 18 soldiers. Four attackers are also killed.