The home secretary, the top civil servant over internal security, held talks with intelligence officials and state-run telecom operators BSNL and MTNL about how the government could access encryption details, the latest global headache for Canadian maker Research In Motion.
A telecoms ministry official, who asked not to be identified, described the talks as inconclusive after the meeting. Another source said private telecom operators could be invited later.
The government first wants to be sure how to pin down Blackberry, the source said, when asked why private operators had not been invited.
An RIM official met India's interior minister separately on Thursday, a government source said. There were no more details.
In a matter of a few weeks, the BlackBerry device -- long the darling of the world's CEOs and politicians, including U.S. President Barack Obama -- has become a target for its encrypted email and messaging services with governments around the world.
The Indian demands follow a deal with Saudi Arabia, where a source said Research In Motion agreed to give authorities codes for BlackBerry Messenger users. The United Arab Emirates, Lebanon and Algeria also seek access.
The government could ask mobile operators to block BlackBerry messaging and email until RIM provides access to data transmitted over the handset, a senior government official said on Wednesday.
Bharti Airtel and Vodafone's India unit are the largest providers of BlackBerry services in India.
A shutdown would affect one million of the smartphone's 41 million users. India is one of RIM's fastest growing markets.
If a shutdown takes effect, BlackBerry users in India would only be able to use the devices for calls and Internet browsing.
India wants access in a readable format to encrypted BlackBerry communication, on grounds it could be used by militants. Pakistani-based militants used mobile and satellite phones in the 2008 Mumbai attacks that killed 166 people.
Officials say RIM proposes tracking emails without sharing encryption details, but that is not enough. A spokesman in India for the Waterloo, Ontario-based company made no comment.
This year, India restricted imports of Chinese telecoms network equipment over security fears. It is also worried about the introduction of 3G wireless services with no monitoring system in place.
RIM, unlike rivals Nokia and Apple, operates its own network through secure services located in Canada and other countries, such as Britain.
The BlackBerry image could suffer if users feel RIM has compromised its Enterprise email system. Corporate and consumer customers both use its BlackBerry Messenger instant messaging.
The German government has urged staffers not to use the BlackBerry and several ministries have banned them. The European Union Commission this month rejected the BlackBerry in favor of Apple's iPhone and HTC smartphones.
India seeks access to both email and Messenger, while Saudi Arabia has only targeted the instant messaging service.
RIM has said BlackBerry's Enterprise system lets customers create their own key, and the company has neither a master key nor a back door to allow it or any third party to access crucial corporate data.
Middle Eastern countries are concerned that BlackBerry users may spread pornography or violate restrictions on contact between unrelated men and women.
Top telecoms firm Bharti Airtel, one of the biggest BlackBerry services providers, ended nearly 0.7 percentage down on the day at 317.55 rupees mainly due to concerns on earnings. The broader market was up 0.02 percent.
RIM shares closed up 1.7 percent at C$58.78 on Wednesday in a Toronto market that was down 2.2 percent.
(Writing by Alistair Scrutton; Editing by Paul de Bendern)