India is extending a crackdown on BlackBerry to other e-mail and internet communications providers, including Skype and Google, a senior government official said on Wednesday.

G.K. Pillai, home secretary, said the government was sending notices to the two internet companies asking them to set up servers in India so that Indian intelligence agencies can monitor e-mail and chat conversations on their systems.

“They have to install servers in India,” Mr Pillai told reporters in New Delhi on Wednesday, adding that “this applies to all”.

The comments come after the expiry of a deadline this week for Research in Motion, the Canadian maker of BlackBerry handsets, to provide security agencies with access to corporate e-mail traffic on its networks.

The government gave RIM a 60-day reprieve but warned that it would have to set up a server within India during this period.

India is concerned that encrypted communications, such as BlackBerry’s corporate e-mail and chat services, could be used by terrorists to plot strikes such as those in Mumbai in 2008.

However, analysts believe the government was forced to back down from its earlier threat to close down BlackBerry services by August 31 amid concern this would disrupt the Commonwealth Games, to be held in Delhi next month.

Google and Skype said on Wednesday they had yet to receive any notices from the government, according to agencies.

RIM’s shares fell to a 17-month low on Tuesday, closing at C$45.70 in Toronto. The stock has fallen more than 18 per cent in August amid concerns over security issues in India and the Middle East.

India is the world’s fastest growing mobile phone market, with more than 600m subscribers and between 10m and 20m new users signing up to its networks every month.