Mahanagar Telephone Nigam Ltd and Bharat Sanchar Nigam Ltd have entered into a strategic alliance, under which the two public-sector telecom companies will jointly offer their voice and data services.

"The alliance will help both the companies have a pan-India presence, with the firms sharing each other's network and putting up a single customer interface window," MTNL executive director R L Dube told reporters on Monday.

BSNL has presence in all circles in the country, except in Mumbai and Delhi, while MTNL has its operations only in these two metro cities.

The move would enable the emergence of the single largest telephony provider in the country, he said, but added that the alliance was not a prelude to the merger of two companies.

Under the pact, the companies had already started offering free roaming services in the country and have simplified connectivity and other procedures, he said.

BSNL chief general manager (Maharashtra telecom circle) R N Bharadwaj said the companies would jointly seek major connectivity contracts in India and abroad.