MUMBAI - India's chief military scientist on Thursday dismissed doubts about the success of the country's nuclear tests in 1998, saying they were "fully successful" and "achieved all objectives".

"I am saddened by unnecessary doubts raised by ex-colleagues," Rajagopala Chidambaram told reporters in Mumbai, referring to claims from a leading Indian nuclear scientist that the tests were only a partial success.

"The May (1998) tests were fully successful in terms of achieving their scientific objectives," he told a news conference.

S. Santhanam, who was a director for the 1998 nuclear test site preparations, has claimed that the tests were only partially successful and the results were much weaker than had been claimed at the time.

Santhanam said the explosions did not yield the desired results as the thermonuclear device tested was a "fizzle", he told a newspaper in August.

The tests under the then-Hindu nationalist government sparked outrage across the world and drew sanctions, but were declared a success and are credited with propelling India to the status of full-fledged nuclear-armed state.

"We have not given details of composition of materials used nor their quantities, due to proliferation sensitivity," Chidambaram, who is the principal scientific adviser to the government, said.

No one outside the design team could comment accurately about the strength of the tests, he added. Five nuclear devices were tested in May 1998 at the Pokhran test range, an isolated region in the northwest desert state of Rajasthan.