In a surprise move, the country's biggest GSM operator said this is a confirmed offer and it reserves the "right to increase this bid in the event of an auction" for such pan-India spectrum.

The company, in a letter to telecom secretary D S Mathur, said, "it seems that a satisfactory outcome of the process underway seems unlikely and the issue is headed for a possible long litigation." 

"The decision to allocate GSM spectrum to CDMA operators seems to be the additional amount that is being charged, we are left with no option but to follow the same practice, albeit at a more realistic amount than what has been currently proposed," company's joint managing director Akhil Gupta said.

The offer of Rs 2,650 crore takes into account that Bharti Airtel would be given no worse off terms and conditions that are being proposed for dual allocation to CDMA operators in license fee and other matters, he said.

"We await the issuance of letter from the department to immediately make the payment and seek this additional spectrum allocation," Gupta said.

The quality of network to serve the growing customer base is of paramount importance and this offer should be seen in the light of the same, he said, adding that denying GSM operators a clear path to grow would derail internationally acclaimed success story of India's telecom sector.

"While attempts are being made to choke the GSM operators of their spectrum needs, the CDMA operators are being happily conferred additional spectrum beyond the highest entitlement," he added.