1947
Britain divides its colony into India and Pakistan. Pakistan is divided into two sections, East Pakistan and West Pakistan. 500,000 people are killed in subsequent fighting.

1948
India establishes the Atomic Energy Commission to explore for uranium ore.

1959
U.S. scientists train Indian scientists in reprocessing, handling of plutonium.

1987
Leading Pakistani nuclear scientist Abdul Qadeer Khan says Pakistan has nuclear bomb.

1988
India tests the Prithvi missile, which is capable of carrying a nuclear warhead into Pakistan.

1996
India and Pakistan refuse to sign the nuclear test-ban treaty.

1997
India moves missiles near Pakistani border.

India's Prime Minister Atal Behari Vajpayee. (Reuters)

May
11: India sets off nuclear devices.

13: India conducts a second round of tests.

13: U.S. imposes economic sanctions against India.

15: India's premier says the country is capable of making a "big bomb" that would be used to defend the country.

17: President Clinton issues a fresh appeal to Pakistan to forgo nuclear tests.

18: An Indian cabinet minister warns Pakistan against trying to boost a separatist Muslim insurgency in Kashmir.

19: Pakistani Prime Minister Nawaz Sharif charges that India has threatened to attack the Pakistani-controlled part of Kashmir.

21: India announces a moratorium on the testing of nuclear weapons. It claims it is willing to negotiate an agreement on a formal test ban.

27: India revises its blanket declaration that it would not use nuclear weapons first in any conflict.

Pakistan Prime Minister Nawaz Sharif. (AFP)

28: Accelerating the arms race, Pakistan conducts five underground nuclear tests. President Clinton criticizes the tests and imposes sanctions.

29: Pakistani officials declare that they would not hesitate to employ nuclear weapons in response to an attack.

30: Pakistan detonates another nuclear device.

31: The mastermind of Pakistan's nuclear program defends his role in developing the country's nuclear capability.

June
01: A newspaper report quotes a top Pakistani scientist as saying that the country has developed a new medium-range missile for nuclear warheads.

July
01: A former Pakistani nuclear weapons engineer warns that his country's top military and intelligence officials discussed plans for a preemptive nuclear strike on New Delhi.

30: The prime ministers of India and Pakistan agree to a new round of security talks but appear as divided as ever about the disputed territory of Kashmir.

May
26: India launches a series of airstrikes at armed Muslim infiltrators in Kashmir. Indian authorities say Pakistan had helped several hundred of them cross into the territory.

27: Pakistan's armed forces said they had shot down two Indian fighter jets over the Pakistani-controlled portion of Kashmir, marking a sharp escalation of military tensions between the world's two newest nuclear powers.

June
11: One day after accusing the Pakistani army of torturing and executing six Indian soldiers, India said it had tapes of telephone conversations showing that Pakistani army officials are running military operations against Indian forces in the Kashmir.

August
18: Indian officials made public a proposed national nuclear arms doctrine under which only the elected prime minister could authorize a nuclear strike and which would allow India to use such weapons only if attacked by another nuclear power.