The United Arab Emirates (UAE) has said that it could move to restrict or monitor BlackBerry mobile phones, as they pose a "national security risk".
The region's telecoms regulator said "BlackBerry operates beyond the jurisdiction of national legislation" as it stores its data offshore.
It said it was concerned that misuse may have "serious social, judicial and national security repercussions".
Critics branded the moves as "repressive".
The media freedom watchdog Reporters Without Borders told BBC News that while the UAE was playing a "technological leadership role in the Arab world" this was backed by "repressive laws" and a "general trend of intensified surveillance".
"Last April, the daily Emarat al Yaoum reported on an interior ministry plan to check the identity of anyone using the internet in public places," said the organisation's Lucie Morillon.
Many mobile phones are already monitored, she said.
The UAE's Telecommunications Regulatory Authority has taken issue with the encrypted networks used by Research in Motion (RIM) - the makers of the Blackberry handset.
These make it difficult for governments to monitor communications.
BlackBerry phones went on sale before the country introduced its safety emergency and national security legislation in 2007
"Currently, BlackBerry operates beyond the jurisdiction of national legislation, since it is the only device operating in the UAE that immediately exports its data offshore and is managed by a foreign, commercial organisation," said a statement from the regulator.
"As a result of how BlackBerry data is managed and stored, in their current form, certain BlackBerry applications allow people to misuse the service, causing serious social, judicial and national security repercussions.
"Like many other countries, we have been working for a long time to resolve these critical issues, with the objective of finding a solution that operates within the boundaries of UAE law."
Research in Motion told BBC News that they had no comment to make "at this point in time".
In June 2009, a separate row erupted between RIM and the state telecoms firm Etisalat after Etisalat released an "update" for the Blackberry handset that, said RIM, was spyware.
"Authorities tried to install spyware on smartphones in July 2009, but users raised such an uproar that they finally abandoned the plan," said Ms Morillon.
Etisalat is a major telecommunications firm based in the UAE, with 145,000 BlackBerry users on its books.
Ms Morillon said there had been a long running campaign to monitor Blackberry transmissions by the UAE authorities.
"There is in particular a very aggressive campaign against the Blackberry messenger, that has become a very popular tool amongst different generations in UAE," she said.
"This is where some sensitive issues are discussed, such as official corruption or when the UAE increased the price of the Oil.
"The latest development appears as one more way to go after the personal data of Blackberry's users, by a regime more and more obsessed by monitoring its citizens," she added.
While 50% of the UAE's population has some kind of internet access, authorities have imposed extensive filtering on what they can view.
Although the government says it is required to fight online pornography, other subject that fall foul of the filtering laws include sites criticising the UAE's human rights record, discussions on the economy and - according to Reporters Without Borders - sites expressing "non-orthodox opinions about Islam".