The Central Bureau of Investigation (CBI) has conducted raids on the Vodafone office in Mumbai and Airtel office in Gurgaon after filing a new case in the 2G spectrum case.

CBI registered a new FIR against ex-telecom secretary Shyamal Ghosh former director of Bharat Sanchar Nigam Limited (BSNL) JR Gupta and telecom giants Airtel and Vodafone.

Immediately after the registering of the case, CBI teams conducted searches at the Vodafone in Mumbai, Airtel in Gurgaon and residences of Ghosh and Gupta, the agency said. Bharti Airtel has responded by saying that it has maintained a high level of corporate governance and regulatory compliance.

"We would like to categorically state that all the spectrum alloted to us from time to time has been strictly as per the stated government policy," a Bharti Airtel spokesperson said.

Vodafone said that it will offer comments later and only said that it is cooperating with the officials.

The CBI has registered the case to check details during the time of late Pramod Mahajan's tenure as Telecom Minister between 2001 and 2003, when the National Democratic Alliance (NDA) was the ruling party.