The Pakistani government plans to shut down BlackBerry Ltd's secure messaging services by December 1 for "security reasons", the Pakistan Telecommunication Authority said on Friday.

Pakistan, a nuclear-armed nation of 180 million people, is plagued by militancy, criminal gangs and drug traffickers.

"PTA has issued directions to local mobile phone operators to close BlackBerry Enterprise Services from Nov. 30 on security reasons," an official with the Pakistan Telecommunications Authority said in a text message.

He asked not to be named due to the sensitivity of discussing communications and intelligence.

BlackBerry was not immediately available to comment.

A report released this week by British-based watchdog Privacy International said Pakistan's powerful military intelligence agency, the Inter-Services Intelligence (ISI), was seeking to dramatically expand its ability to intercept communications.

BlackBerry encrypts data such as emails and its BlackBerry Messenger messages sent between a user's phone and public networks, ensuring greater privacy for users but making life harder for police and intelligence agencies.

The company has faced similar problems in the past in India, the United Arab Emirates, Saudi Arabia and Indonesia.

The Privacy International report said the ISI had few legal checks on their surveillance.

"Pakistan's intelligence agencies have abused their communications surveillance powers, including by spying on opposition politicians and Supreme Court judges. Widespread Internet monitoring and censorship has also been used to target journalists, lawyers and activists," the report said.