New Delhi, May 11: National Security Council chairman K.C. Pant on Monday described the nuclear tests as "courageous and historical."

Mr Pant, a former defence minister, while congratulating the scientists involved, said: "The tests would add to the strength of the country not only militarily but also psychologically. "

Asked about possible sanctions against India following the tests, Mr Pant said: "I believe every country has to do everything possible in the interests of its national security. The onus of what steps are necessary for the same is on us."

The BJP said the nuclear tests demonstrated the government' s commitment to uphold the nation's security and that "unlike previous regimes, it shall not give in to international pressure."

"It is a re-assertion of our sovereign right to decide for ourselves how best it meets our security concerns and it is a repudiation of the policy of nuclear apartheid that the West sought to impose on us," BJP president Kushabhau Thakre said in a statement.

The United Front called upon the government to launch a "diplomatic offensive" to counter the fallout of the nuclear tests, but complimented the Indian scientists on having accomplished "yet another first-rate technological feat."

"India has been a de facto nuclear weapon state for more than two decades and with this development, the status has become de jure," Front spokesman S. Jaipal Reddy said.

The Samajwadi Party congratulated the scientists, particularly Dr Abdul Kalam, for their achievements at Pokhran. "There is nothing to fear as far the country's security is concerned," party general secretary Amar Singh said.

Janata Party president Subramanian Swamy said the nuclear tests should be followed up by formulation of a global strategic policy. "The greatest error that India committed in 1974 was to have an underground test without a concomitant strategic policy," Dr Swamy said.