Google and Skype could follow BlackBerry onto a list of banned messaging services unless the companies satisfy the Indian government security concerns.
The news comes after authorities in the country issued an ultimatum to Canadian firm Research In Motion (RIM), which makes the BlackBerry smartphone, giving it until 31 August to provide security services with unencrypted access to messages sent via the device.
If RIM fails to do so, certain key BlackBerry services could be blocked within India.
In addition to BlackBerry services, Indian authorities have been looking into messaging services from Google, Skype and others for more than a year.
The move is part of an attempt to combat militants and cybercrime in what is the world's largest mobile phone market, a government source told reporters today.
It is claimed that Pakistan-based militants used mobile and satellite phones during a series of co-ordinated attacks in Mumbai in 2008, which killed 166 people. Police also suspect the attackers used IP telephony to organise the assaults.
A senior interior security official, who declined to be identified, told news agency Reuters: "Wherever there is a concern on grounds of national security, the government will want access and every country has a right to lawful interference.
Mobile phone providers have also come under scrutiny, with strict import rules governing the purchase of network equipment and temporary bans on Chinese manufacturers Huawei Technologies and ZTE Corp over fears of embedded spyware.
India's threatened ban on BlackBerry devices follows a compromise reached by RIM with authorities in Saudi Arabia, under which the company agreed to issue security services with access codes to track email.
Industry insiders expect some form of agreement to be reached with the Indian government.
"We don't expect a ban, actually. There will be some solution before the deadline," a senior official with an Indian mobile phone operator told Reuters.
RIM insisted in a statement on Thursday that it tried to cooperate as fully as possible with governments, and demanded equal treatment for all service providers. And earlier offer to allow tracking of email has been refused, with authorities holding out for readable, unencrypted access to all messages.
If a ban were to be imposed, it would strike a serious blow against RIM in its fastest growing market. India currently accounts for one million out of the device's 41 million global user base.