Saudi Arabia suspended BlackBerry messaging services on Friday, users said as concerns spread across the Middle East and parts of Asia over security issues with the popular smartphones.
BlackBerry subscribers in the ultra-conservative Muslim kingdom said they were no longer able to use the messaging services from around midday (0900 GMT).
"It has stopped," said one in the western port of Jeddah, adding his friends also noticed the services had been phased out on their devices.
The Saudi telecommunications authority had announced on Tuesday that it ordered the country's three mobile phone providers to block the services or face a 1.3-million-dollar fine.
The regulator said "the way BlackBerry services are provided currently does not meet the regulatory criteria of the commission and the licencing conditions," in a statement carried by Saudi Arabia's official news agency SPA.
BlackBerry's encrypted emails and data are stored on servers in Canada, the headquarters of its maker, Research in Motion, meaning third parties like intelligence agencies cannot monitor communications.
There are more than 700,000 BlackBerry subscribers in Saudi Arabia, a highly security-conscious monarchy with a rigid Islamic social code and strictly censored Internet service.
An official from one of the mobile providers, speaking on condition of anonymity, had said the companies would comply with the regulator's decision for security reasons, as well as to avoid being fined.
The shutdown comes five days after the United Arab Emirates announced it would cut off the messenger, email and web browsing services of BlackBerrys in the Gulf state on October 11 over security concerns.
Lebanon on Thursday became the latest country in the Middle East to voice security fears over the handheld devices as the United States stepped into the growing row.
Lebanon's telecommunications regulator said Beirut would assess security concerns about the smartphones after the arrest of several telecoms employees suspected of spying for Israel.
In Bahrain, a spokesman for mobile provider Batelco told AFP his company already has alternative plans in case the Gulf state follows suit with a ban.
And in Kuwait, a VIVA Telecom spokesman said: "Until now we were not given any orders on new means of dealing with BlackBerry and the company will not block any of those devices' services."
India is mulling a similar move and, while Indonesia denied it was considering a suspension of BlackBerry services on Thursday, it did not rule out the option.
Secretary of State Hillary Clinton said on Thursday that the United States would soon hold talks with the United Arab Emirates and other countries about the issue.
"We are taking time to consult and analyse the full the range of interests and issues at stake because we know that there is a legitimate security concern," Clinton said, adding however that there was also a "legitimate right of free use and access."
The Saudi daily Arab News, in a report this week on its website, said an online survey of 331 people found 178 people opposed to the BlackBerry ban and 153 supporting it.
It said those who disagreed complained that no prior notice was given, with some having bought their BlackBerrys just days ago now lumbered with an expensive device that will not work as a smartphone.
The 153 people in the poll who supported the move said BlackBerrys "have had a very negative effect on the youth."
A woman, named as Um Aisha, told the paper she had confiscated her daughter's BlackBerry after she became overly attached to it to the point where it was affecting her health.
"My daughter collapsed once. When we took her to hospital the doctor said she was suffering from fatigue... She reads every SMS she receives and even replies to them late at night," Um Aisha said.