Former prime minister Indira Gandhi had considered preventing Pakistan from becoming a nuclear state by attacking its strategic programme installations.

A Central Intelligence Agency (CIA) document titled "India's Reaction to Nuclear Developments in Pakistan" was declassified in June this year. The paper highlighted that Gandhi was unhappy over US move to arm Pakistan with F-16 fighter jets in the early 1980s.

The paper dated September 8, 1981 claimed that New Delhi was also concerned about advances made by Pakistan in acquiring a nuclear weapon. India was not off the mark in its assessment as Washington had the similar lead.

The document said India had considered an extreme option to start military conflict with Pakistan an aim to destroy its nuclear installations.

"In the extreme case, if Indian concerns increase over the next two or three months, we believe the conditions could be ripe for a decision by prime minister Gandhi to instigate a military confrontation with Pakistan, primarily to provide a framework for destroying Pakistan's nuclear facilities," said the US report.

Indira Gandhi also activated India's own programme to test a device on short notice when she learnt that Pakistan was close to enriching weapon grade uranium and producing plutonium.

"In February (1981), excavation was begun in the Thar desert to permit the underground explosion of an Indian test device on short notice," the report said. In three months, India was ready to test a 40-kiloton nuclear device.

India had planned to test the device within a week of feared Pakistan's explosion. "Evidently, the Indian government calculated that a Pakistani nuclear explosion per se would not constitute a national security threat and that the damage to India's image of pre-eminence in the region could be minimised by a resumption of the peaceful nuclear explosive (PNE) programme," said the report.