At the time of partition, the princely state of Kashmir, though ruled by a Hindu Maharajah, had an overwhelmingly Muslim population. When the Maharajah hesitated in acceding to either Pakistan or India in 1947, some of his Muslim subjects, aided by tribesmen from Pakistan, revolted in favor of joining Pakistan. In exchange for military assistance in containing the revolt, the Kashmiri ruler offered his allegiance to India. Indian troops occupied the eastern portion of Kashmir, including its capital, Srinagar, while the western part came under Pakistani control.

India addressed this dispute in the United Nations on January 1, 1948. One year later, the UN arranged a cease-fire along a line dividing Kashmir but leaving the northern end of the line undemarcated and the Vale of Kashmir (with the majority of the population) under Indian control. India and Pakistan agreed with Indian resolutions that called for an UN-supervised plebiscite to determine the state's future.

Full-scale hostilities erupted in September 1965, when India alleged that insurgents trained and supplied by Pakistan were operating in India-controlled Kashmir. Hostilities ceased 3 weeks later, following mediation efforts by the UN and interested countries. In January 1966, Indian and Pakistani representatives met in Tashkent, U.S.S.R., and agreed to attempt a peaceful settlement of Kashmir and their other differences.

Following the 1971 Indo-Pakistan conflict, President Zulfiqar Ali Bhutto and Indian Prime Minister Indira Gandhi met in the hill station of Shimla, India, in July 1972. They agreed to a line of control in Kashmir resulting from the December 17, 1971, cease-fire, and endorsed the principle of settlement of bilateral disputes through peaceful means. In 1974, Pakistan and India agreed to resume postal and telecommunications linkages and to enact measures to facilitate travel. Trade and diplomatic relations were restored in 1976 after a hiatus of 5 years.

India's nuclear test in 1974 generated great uncertainty in Pakistan and is generally acknowledged to have been the impetus for Pakistan's nuclear weapons development program. In 1983, the Pakistani and Indian Governments accused each other of aiding separatists in their respective countries -- Sikhs in India's Punjab state and Sindhis in Pakistan's Sindh province. In April 1984, tensions erupted after troops were deployed to the Siachen Glacier, a high-altitude, desolate area close to the China border left undemarcated by the cease-fire agreement (Karachi Agreement) signed by Pakistan and India in 1949.

Tensions diminished after Rajiv Gandhi became Prime Minister in November 1984 and after a group of Sikh hijackers was brought to trial by Pakistan in March 1985. In December 1985, President Zia and Prime Minister Gandhi pledged not to attack each other's nuclear facilities. (A formal "no attack" agreement was signed in January 1991.) In early 1986, the Indian and Pakistani Governments began high-level talks to resolve the Siachen Glacier border dispute and to improve trade.

Bilateral tensions increased in early 1990, when Kashmiri militants began a campaign of violence against Indian Government authority in Jammu and Kashmir. Subsequent high-level bilateral meetings relieved the tensions between India and Pakistan, but relations worsened again after the destruction of the Ayodhya Mosque by Hindu extremists in December 1992 and terrorist bombings in Bombay in March 1993. Talks between the Foreign Secretaries of both countries in January 1994 ended in deadlock.

More recently, the Indo-Pakistani relationship has veered sharply between rapprochement and conflict. After taking office in February 1997, Prime Minister Nawaz Sharif moved to resume official dialog with India. A number of meetings at the foreign secretary and prime ministerial level took place, with positive atmospherics but little concrete progress. The relationship improved markedly when Indian Prime Minister Vajpayee traveled to Lahore for a summit with Sharif in February 1999. There was considerable hope that the meeting could lead to a breakthrough.

In spring 1999, infiltrators from Pakistan occupied positions on the Indian side of the Line of Control in the remote, mountainous area of Kashmir near Kargil, threatening the ability of India to supply its forces on Siachen Glacier. By early summer, serious fighting flared in the Kargil sector. The infiltrators withdrew following a meeting between Prime Minister Sharif and President Clinton in July. Relations between India and Pakistan were particularly strained during the 1999 coup in Islamabad. Then, just weeks after the September 11, 2001, attack on the United States, an attack on India's Parliament on December 13 further strained this relationship.

The prospects for better relations between India and Pakistan improved in early January 2004 when a summit meeting of the South Asian Association for Regional Cooperation (SAARC) permitted Indiaís Prime Minister Vajpayee to meet with President Musharraf. They improved when President Musharraf met with Indiaís Prime Minister, Manmohan Singh, for a meeting in New York in October 2004. Announcements of additional steps aimed at improving relations occurred when Indian Foreign Minister Singh visited Islamabad in February 2005 and in April 2005 when President Musharraf traveled to India to view a cricket match and hold discussions. In the wake of the October 2005 earthquake-created humanitarian disaster the two countries continued their cooperative measures.

Pakistan historically has provided military personnel to strengthen Gulf-state defenses and to reinforce its own security interests in the area.