By Zubair Ahmed
BBC News, Mumbai
India's nuclear tests shocked the world
India should conduct further nuclear tests to establish itself as a true nuclear power, the former head of India's main nuclear body has said.
PK Iyengar told the BBC that he made it clear in 2002 that India's nuclear tests were inconclusive and ambiguous.
His comments come as atomic scientist K Santhanam, who was associated with India's 1998 nuclear tests, said they were not as successful as claimed.
This was dismissed by the government and former colleagues.
The Indian tests led to similar tests by Pakistan, raising fears of a nuclear conflict between the two countries.
"If India wants to declare itself as a nuclear power and confirm to the military that you have all the means of designing a thermo-nuclear device which can go into a missile, which can be dropped from an aircraft or can be launched from a submarine, you need many more tests," Mr Iyengar, the former chairman of Atomic Energy Commission (AEC), told the BBC.
Mr Iyengar also said that India's 1998 nuclear test was not a deterrent against China, though it was against Pakistan.
"The Chinese are aware of it and that should be a worry for India," he said.
Mr Iyengar's endorsement of Mr Santhanam came soon after the latter's claim was dismissed by the Indian government.
On Wednesday, Mr Santhanam claimed that the "yield in the thermo-nuclear device test was much lower than what was claimed".
He said one of the tests - on a hydrogen bomb - had not worked and that India would have to carry out more tests for a credible nuclear deterrent.
Mr Santhanam is a respected Indian atomic scientist who was project director of the 1998 nuclear tests.
His remarks on India's nuclear capabilities sparked protests from the government as well as some fellow scientists.
The government swiftly dismissed the claim saying it was based on no scientific evidence.