CBI Director A P Singh today contradicted Telcom Minister Kapil Sibal on his claim that the 2G spectrum allocation had caused "zero loss" to the national exchequer as he appeared before Parliament's Public Accounts Committee (PAC).

Singh was quizzed by the members of the Committee on various aspects of the 2G spectrum allocation which the CBI is investigating.

"As far as he (Singh) has seen the case, to say 'zero loss' is wrong," PAC chairman Murli Manohar Joshi told a press conference after the meeting.

A member of the Committee said the CBI chief was of the view that it would be "wrong to say that there was zero sum loss in allocation of 2 G spectrum on first-come-first-serve basis."

This assertion of the CBI chief contradicts Sibal who had claimed that the 2G spectrum allocation had caused "zero loss" to the exchequer and rubbished as "utterly erroneous" the CAG's calculation that the presumptive loss was to the tune of Rs 1.76 lakh crore.

The CBI, in its FIR in the 2G case, has said the losses could be to the tune of Rs 22,000 crore.

The CBI Director was asked about the methodology used by the agency to calculate the losses caused by the alleged irregularities in the 2G spectrum allocations.

He said he would be unable to accurately quantify the loss to the exchequer as his focus was on unravelling the criminal aspect of the alleged scam.

He told the members that he would get back to the PAC on the matter.

To questions on whether former Telecom Minister Arun Shourie would be called by the PAC, Joshi pointed out that the CBI has already asked him to appear before it on February 21.

Sibal had described as "utterly erroneous and without any basis" the estimated loss of Rs. 1.76 lakh crore arrived at by the CAG on account of allocation of 2G spectrum to telecom operators.

Sources said the CBI Director was asked as to why the agency had taken a position initially against the Supreme Court monitoring the 2G case.

Singh reportedly told the Committee that the initial position was based on certain legal terms, but when it realised the gravity of the situation it agreed for monitoring by the apex Court.

CBI Deputy Inspector General S K Palsania took most of the questions from the committee members. Singh took over as CBI Director on November 30 last year.

Terming Sibal's remarks as an insult to Parliamentary system, Joshi had written to Lok Sabha Speaker Meira Kumar questioning Sibal's critical comments against the CAG.

Asked about the letter, Joshi said he had received a reply and members of the PAC felt the issue should be discussed further with the Speaker.

"I will be meeting the Speaker to discuss the matter," he said without giving any timeframe.

To a question about Prime Minister Manmohan Singh's offer to appear before PAC, Joshi said his letter is "safe" with the PAC. "If a decision is taken, you will come to know," he said.

He said the Prime Minister's Office had provided a lot of information to the PAC and more information is being sought from it.

On the possibility of summoning Sibal, he said a decision will be taken by the PAC members.

To a question on whether the PAC would lose relevance if the government decided to set up a Joint Parliamentary Committee to look into the issue, Joshi said "PAC is a Constitutional body and it will continue with its work."

He said the PAC would not be affected by any such development. "If the Supreme Court is doing its work, if the CBI and PAC are doing their work, the JPC will also do its work," Joshi said.