India prime ministerial frontrunner Narendra Modi said he was committed to a policy of "no first use" of nuclear weapons, seeking to assuage concern after his Hindu nationalist BJP party vowed to revise the nuclear doctrine if elected to power.
India declared itself a nuclear weapons state after carrying out tests in 1998, which were followed by tests by Pakistan. Since then both have been developing nuclear weapons and testing longer range missiles.
"It is necessary to be powerful - not to suppress anyone, but for our own protection," Modi said in an interview with the ANI television service.
But he said he would pursue a policy of continuity based on the approach of former Bharatiya Janata Party (BJP) prime minister Atal Bihari Vajpayee who declared a policy of "no first use" of nuclear weapons after ordering the tests.
"'No first use was' a great initiative of Atal Bihari Vajpayee - there is no compromise on that. We are very clear. 'No first use' is a reflection of our cultural inheritance," Modi told ANI.
His comments came a week after the BJP unveiled its manifesto, pledging to review the nuclear doctrine, whose two main pillars were a "no first-use" commitment and building a credible but minimum nuclear arsenal.
The pledge, to "study in detail India's nuclear doctrine, and revise and update it, to make it relevant to challenges of current times", gave no specifics but raised concerns among former US diplomats that the policy of "no first use" would be abandoned.
Two sources involved in the drafting of the manifesto said the party wanted to reconsider the "no first use" policy in the wake of Pakistan's advances in the area of tactical nuclear weapons.
Pakistan does not have a no first policy and is building nuclear weapons programme designed to deter India and neutralise its much larger conventional military.
India also has concerns about China, which has bigger military as well as more advanced strategic weapons arsenal.