Indian Prime Minister Atal Bihari Vajpayee has visited the site where his country set off five nuclear explosions last week.
He says India is ready to pay any price for its security.
But he also offered to hold talks with Pakistan - if Islamabad called for them.
Prime Minister Atal Bihari Vajpayee arrived at this desert test site on Wednesday where last week Indian scientists detonated five nuclear devices.
Pokaran was also the site of India's first and, until last week only, nuclear test in 1974.
Vajpayee peered into the crater caused by the largest blast that was 15 metres (yards) deep and 30 metres (yards) wide.
Referring to a ban on future tests, Vajpayee said India needed to settle key issues before it can sign the Comprehensive Test Ban Treaty.
He didn't elaborate, but his remarks were seen as rejection of the demand that India sign the treaty unconditionally.
The U-S, Japan and other industrialised countries imposed economic sanctions against India to underscore their condemnation of Vajpayee's decision to go ahead with nuclear testing, fearing an arms race between India and Pakistan.
Vajpayee also ridiculed the five recognised nuclear powers, saying that they preached peace to India, but stockpiled nuclear weapons themselves.
Pakistan is facing pressure from Western countries to refrain from testing its own nuclear capability in response to India's five test explosions last week.
India and Pakistan have fought three wars in the past 50 years.
Vajpayee praised Indian soldiers guarding the testing site at Pokaran, 550 kilometres (330 miles) southwest of New Delhi, and said he was prepared to "pay any price" to preserve the country's national security.
He called the tests provided a deterrent against neighbors China and Pakistan - the first a declared nuclear power and the second a suspected one.
Vajpayee offered to talk with Pakistan, as he has several times since taking office two months ago.
But he said it was up to Islamabad to make the next move toward resuming a dialogue.
High-level talks between the two hostile neighbours broke down last year over how to deal with the issue of Kashmir, the former princely state claimed by both countries.
India's Defence Minister said the visit proved to him that the tests had been a success.
''My feelings are that I am satisfied with the decision that we took. I am satisfied in the manner in which the decision was implemented, by our scientists, engineers, and by the personnel of the army and the air force who are involved in it. I am satisfied with the results, as we see them on the ground, here and elsewhere in this Pokaran region.''
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Vajpayee said the nuclear tests were a cause for national pride, proving the sophistication of Indian science.
Local residents who waved banners and chanted Vajpayee's name were not the first to agree.
There have been celebrations across India since the tests were carried out.
The festive atmosphere was only slightly dampened by a nearby protest from about 60 villagers.
Vajpayee's convoy drove past without stopping as they complained of ailments they said were caused by the test and demanded compensation for damage to their homes.