NEW DELHI: India's top mobile phone company Bharti Airtel announced Friday it had crossed the 100-million subscriber mark and expected to double that number within the next three years.

India is the world's fastest-growing mobile market, driven by the cheapest tariffs globally of less than two cents a minute.

"We are proud to have led the telecom revolution," Bharti chairman Sunil Bharti Mittal said, announcing the corporate milestone.

The company, founded in 1995, notched up its first 25 million customers in July 2006 and crossed the 75 million customer mark in August 2008.

Mittal, listed by Forbes magazine as one of India's billionaires, said he expected the company to add another 100 million customers in the next three years.

Much of Bharti's growth has been driven by its rural customer base which makes up 60 percent of its clients.

"Our focus on rural penetration and customer affordability led to strong growth," said Mittal.

Mobile phone growth has so far been mainly confined to India's cities but analysts say the real prize lies in its vast rural hinterland where 70 percent of the more than 1.1 billion population lives.

India added a record 15.6 million cellular users in March as more rural consumers snapped up mobile phones, latest industry data shows.

For rural customers, Airtel said it has set up 14,000 service centres and expects to have over 100,000 such centres across the country by March 2010.

The New Delhi-based company announced a 26 percent jump in net profit for last year to 84.69 billion rupees (1.68 billion dollars) on a 37 percent increase in revenues to 369.61 billion rupees.

India is the world's second-largest cellular market after China.

Bharti Airtel, in which Singapore's SingTel owns more than 30 percent, has retained its number one spot in India despite strong competition from rivals Reliance Communications and Vodafone Essar.