Japan's NTT Docomo,the No.1 mobile operator in Japan, has announced a strategic alliance with Tata Teleservices, the telecommunications division of India's largest company.

NTT Docomo will acquire 26 percent of Tata Teleservices for $2.7 billion. Docomo will also join Tata Sons, primary owner of the telecom unit in making a tender offer for 20 percent of the unit's shares. The two companies said in a statement that the deal will help Tata, now No.6 in India, expand more rapidly in the hot Indian telecom market.

NTT Docomo operate one of the most advanced mobile networks in the world with some 53 million customers in Japan. Tata Teleservices has 30 million subscribers in India, one of the world's fastest growing mobile markets.

Its parent company, with 350,000 employees in 80 countries in engineering, outsourcing, chemicals and metals, reported revenues of $62.5 billion in its last fiscal year. Tata made headlines earlier this year when it announced  the world's least expensive car, the $2500 Nano.

The deal is Docomo''s largest in eight years and reflects the attraction of a telecom market that adds 9 million new users each month. According to analysts, Docomo has refocused on developing countries after a failed investment in Hutchinson 3G UK forced it to write off $15 billion between 2001 and 2004. The company said  earlier that it was interested in investing in markets like Bangladesh, Vietnam, Cambodia and Laos, where cell phone usage is still low. In  June, Docomo Vodadone made  a $350 million investment for a 30 percent stake in TM International (Bangladesh).

Vodafone, the world's largest mobile-phone company, paid $13.1 billion in May 2007 for a 67 percent stake in Vodafone Essar, formerly known as Hutchison.

As of Sept. 30, the number of subscribers in India was up 51 percent in a year to 315.3 million, according to the Telecom Regulatory Authority of India.

By comparison, Japan added 0.4 percent customers to 104.8 million, based on figures from the nation's telecom trade association.  The country gained 5.59 million mobile users in 2007, or about 60 percent of India's monthly additions.