New Delhi: Seven top executives of major organisations including the Tata group were on Thursday questioned by CBI in connection with its probe in the 2G spectrum scam.

CBI officials said R Krishna Kumar and Sanjay B Ugale, Chairman and Managing Director respectively of Tata Realty and Infrastructure, Dilip Modi, Managing Director, Spice Telecom, S Sarvana, Director and V Srinivasan, Group Chief Executive Officer of Siva Group of Companies, Shamik Das, CEO, S Tel and Sandip Basu, CEO of Loop Telecom were quizzed for over four hours at the agency's office here.

They were asked to clarify the roles played by their respective organisations and possible stakes in other telecom companies that may have acted as a front for getting second generation technology licenses from Telecom ministry.

Loop had got licenses for 21 circles when the spectrum was allocated during the first stint of jailed former Telecom Minister A. Raja between September 2007-January 2008.

The two officials of Tata Realty and Infrastructure were asked about the purported Rs 1,600 crore loan extended to Unitech to procure the spectrum.

This is the second time that Ubale and Basu have been quizzed by the CBI in connection with the firm's alleged linkages with Unitech, one of the two companies which have been mentioned in the FIR filed by the agency on October 21, 2009, they said.

The CBI had earlier questioned Sanjay Chandra of Unitech on issues relating to offloading of majority stake to Norway based company Telenor after getting 2G spectrum license.

CBI is probing whether Tata Real Estate had paid Rs 1,600 crore to Unitech for a land deal at a time when the the real estate company was applying for 2G license in 2007.

Unitech has claimed that it has been cooperating with all investigating agencies from the very beginning as it has nothing to hide.

The charges against Unitech, according to CBI's FIR, was that it offloaded over 60 per cent of its stake to Telenor and earned a profit of 267 per cent even before the service roll-out.

"M/s Unitech was alloted UAS licences for 22 circles for Rs 1658 crore. It offloaded its 60 per cent of shares in the licences to Telenor of Norway for Rs 6100 crore even before the roll-out," the FIR said.

According to the FIR, "estimated loss to the government by grant of licences to these two companies (Swan and Unitech) alone comes to Rs 7,105 crore. On pro-rata basis, the estimated loss for all the 122 circles is more than Rs 22,000 crore."

CBI officials had Thursday quizzed Chairman of Sistema Shyam Teleservices Rajiv Mehrotra in connection with the scam. A joint venture between India's Shyam group and Russian giant Sistema, Sistema-Shyam is the only new telecom operator which is offering CDMA based services across the country. It is alleged that undue haste was shown in issuing in principle approval for use of GSM technology to the company in one circle, sources said.

The CBI had also questioned Kaliaperumal, brother of Raja. Raja's close aide Sadiq Batcha, who is the promoter of Green House Promoters, a Chennai-based export house, which has come under the scanner of the CBI and the Enforcement Directorate in the scam, has also been questioned by the CBI.

Former Telecom Minister Arun Shourie is also likely to appear on Friday before the CBI for questioning in connection with the agency's probe into possible criminal aspects in the telecom policy since 2001. Shourie had held the telecom portfolio between January 2003 and May 2004 in the NDA regime. According to the CBI, nearly 50 licences were given out then on a first-come-first-serve basis and Bharti, Vodafone and Idea were among the beneficiaries of the policy.