``With the May 1998 Pokhran tests, we have generated the desired data. Hence, india has unilaterally declared a test moratorium. We are capable of conducting underground sub-critical tests after signing the CTBT, if necessary,'' Kalam said here.

On his detailed discussion on the post-nuclear test status with Atomic Energy Commission Chairman R Chidambaram, Kalam said ``from the scientific and technical angle, it is our considered view that no further nuclear tests are necessary and subscribing to the CTBT would not create difficulties for our nuclear status''.

The CTBT text, Kalam said, had two major loopholes -- one regarding the right to conduct sub-critical laboratory testing for weapon design simulation and the other regarding the option to withdraw fromthe treaty with a six month notice under reasons of supreme national interest.

``The relevance of these two clauses is only for those who had nuclear weapons,'' he said clarifying that the two clauses were of no use to countries which did not possess nuclear weapons.

Replying to questions, Kalam, who is also the chief of Defence Research and Development Organisation (DRDO), said India had come a long way since it conducted its first nuclear test in 1974 as the country's scientists had been working on the data base to improve the design of nuclear weapons and modernise them.

``The required data have been obtained through the five tests in Pokhran in May for carrying out simulation for future development by the scientists and technologists,'' the top scientist said.

Asked if India possessed a boosted fission device, the second stage in the development of a hydrogen bomb, Kalam said ``we have graduated beyond that stage. We tested a thermonuclear device (hydrogen bomb) on May 11 with a 45 kilotonneyield''.

To a question about India's capability of weapon design simulation, he said the country had several super computers in various research institutions including the Atomic Energy Commission and there would be no hurdle on this score.

He said India was among the first countries to propose CTBT in 1962 when it could have served as an effective nuclear arms control measure to prevent proliferation in a real sense.

However, the intensity of nuclear proliferation increased and thousands of tests were conducted by the five nuclear weapon holding countries -- the US, Russia, Great Britain, France and China. Noting that the US and erstwhile Soviet Union had accumulated tens of thousands of nuclear warheads each, he said ``after a record 22 years of self-imposed restraint in refusing to sign the CTBT, India signaled its seriousness about the nuclear option and finally exercised it may this year''.

He said ``one must realise that France and China also would have opposed the CTBT, if somehow they wereunable to conduct the additional tests they carried out recently''.

Coming to India in the present, Kalam asserted that we were a nuclear weapons state, and ruled out any roll back of the nuclear weapons programme.

Referring to the May 11 Pokhran tests, he said the total yield generated by three simultanous explosions comprising a hydrogen bomb, an atom bomb and a sub-kilotonne nuclear device was 60 kilotonnes.

This had been confirmed by New Scientist, a reputed international scientific journal, after analysis of data from may Pokhran tests from 250 seismic stations the world over, he said.