A comment on its nuclear programme by a top Iranian leader has upset India, which asserted on Monday that New Delhi was a responsible nuclear weapon state and has always been in compliance with its obligations under international treaties and agreements.

"We have seen the comments regarding India in a recent interview. We regret this reference to India," Navtej Sarna, External Affairs Ministry spokesman said, referring to the remarks of Ali Larijani, Secretary of Iran's Supreme National Security Council.

Larijani, while criticising the doubts cast on Iran's nuclear programme by the United States, had compared Tehran's case with that of India.

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"It does have nuclear weapons but the US has extensive relations in the nuclear field (with India). This dual standard is detrimental to international security," he had said.

Sarna said India had 'consistently maintained that it is a state's sovereign right to enter into treaties and international agreements'.

The spokesman said every country 'must fully comply with its international obligations and commitments and in a transparent manner'.

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India, Sarna maintained, 'is a responsible nuclear weapon state and has always been in compliance with its obligations under international treaties and agreements'.