"We are now working very closely with China Mobile for the launch," said Katie Lee, spokeswoman for RIM in the Asia-Pacific region, in an e-mail.

The deal would make BlackBerry available to the world's largest mobile-phone market, giving RIM a shot at attracting a larger share of the world's users with its push e-mail services and devices.

The number of Chinese mobile subscriptions reached 404 million at the end of February, according to Chinese government statisticians. Over half of Chinese users rely on China Mobile for their wireless service, a total of 254.9 million as of the end of February, according to the company. China Mobile alone has more mobile phone subscribers than the entire U.S.

Lee also confirmed that RIM has no relationship with a rival service in China called RedBerry.

The RedBerry push e-mail service was announced earlier this month by China United Telecommunications Corp. (China Unicom), the country's second-largest mobile operator (see "BlackBerry, meet China Unicom's RedBerry"). The company said it chose the name in part due to "people's familiarity with the BlackBerry brand name," which it described as the most successful application of push e-mail technology.

The BlackBerry service is currently available in several Asian markets, including Hong Kong and Singapore.