Saudi Arabia's telecoms watchdog has called on telecoms firms in the country to block the messenger function on Blackberry handsets from Friday.
The watchdog said the ban would last until the state's three mobile phone operators "fulfil the regulatory requirements it has requested".
But the Communications and Information Technology Commission (CITC) did not reveal what these requirements were.
The United Arab Emirates threatened on Sunday to ban some Blackberry services.
11:36 am on Aug 6, 2010 (gmt 0)
There are rumours that RIM will solve the conflict with Saudi Arabia by placing a message server inside the country. That won't solve the problems with other countries though. Algeria has threatened with a ban of the devices in their country, just as Lebanon. And also large countries like India and China are concerned about the encryption and off-shore message storage functionality of Blackberries.
7:58 pm on Aug 6, 2010 (gmt 0)
So in all those countries, it is a crime to communicate with the outside world unless the government can eavesdrop?