Her comments came during a conference celebrating the legacy of India's freedom champion Mahatma Gandhi, who chose non-violence as his tool to campaign against 300 years of British colonial rule.

"Nuclear weapons became a strategic compulsion for India, born out of its failure to persuade the world to abolish them," she told international delegates in New Delhi.

"They (nuclear weapons) have become the very currency of power," Gandhi said.

"But the commitment (of India) to comprehensive, universal nuclear disarmament remains our profound conviction which we intend to carry forward," the Italian-born widow said.

India, which refuses to sign the Comprehensive Test Ban Treaty or the Nuclear non-Proliferation Treaty, conducted a series of nuclear weapons tests in May 1998 and then declared an unilateral moratorium on further testing.