The company, which has faced similar problems in the past in India, the United Arab Emirates, Saudi Arabia and Indonesia, had said last month it would delay shutting down its operations in Pakistan until December 30.
State-run Pakistan Telecommunication Authority had in July demanded that the company give access to its BlackBerry Enterprise Services (BES), which encrypts data such as emails and instant messages.
BlackBerry, formerly known as Research In Motion Ltd, said on Thursday it would not provide access to its BES servers.
A report released in July 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.
Shares of the company were down 0.46 percent at C$12.91 on Thursday on the Toronto Stock Exchange.
© Thomson Reuters 2016
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