Senior Bharatiya Janata party leader Jaswant Singh Tuesday found himself at the receiving end in the Rajya Sabha with Prime Minister Manmohan Singh asking him to name the 'mole' in the Prime Minister's Office during Narasimha Rao's regime who "leaked" nuclear secrets to the US.

"The honourable member should answer the simple question. Who is the mole and why is he shying away from that," the prime minister asked him during an acrimonious debate on the issue.

In the midst of heated exchanges between the treasury and opposition benches, Jaswant Singh said he was trying to establish the centrality of the US efforts to "control, curb and put in tight wrap India's nuclear programme".

This sparked off another bout of protests from the ruling side which said the BJP leader's comments had no relevance to the 'mole' issue and he was not naming the person. Jaswant Singh said he was trying to answer all queries if members exercise patience.