The maker of BlackBerry devices says tighter restrictions on the popular gadgets proposed by Emirati authorities would likely apply to other smartphones too, raising new questions about data freedom in the Gulf Arab nation.

The United Arab Emirates' telecommunications regulator has outlined plans to limit access to the Blackberry Enterprise Server system, which provides the most secure form of communication on the handheld devices. It is used by many international companies and government agencies to keep emails and other data safe.

Only organizations with 20 or more BlackBerry accounts would be allowed to use the service under the UAE's proposed new rules. Others would need to rely on a less-secure system that analysts say is easier for authorities to monitor and could cause accessibility problems for corporate users.

The proposed policy shift opens a new front in the Emirates' push to gain greater control over smartphone data. Barely six months ago, the federation backed down from a threat to impose a sweeping ban on the most popular BlackBerry services amid concerns about security.

"It seems very arbitrary. ... All I can think is that they're trying to address their security concerns by limiting the use of this more secure platform to larger companies and organizations," said Matthew Reed, a Dubai-based analyst at Informa Telecoms & Media, a research firm. "It will inconvenience quite a few people" who work for smaller companies and branch offices, he said.

The Telecommunications Regulatory Authority on Saturday sought to assure customers that all BlackBerry services will continue. But it has not explicitly backed down from plans to limit access to the most secure service.

Research in Motion Ltd., the Canadian company that makes BlackBerrys, said in an emailed statement Sunday it has been in contact with the regulator and understands that other smartphone makers could also face new restrictions.

"The TRA has confirmed to RIM that any potential policy regarding enterprise services in the UAE would be an industrywide policy applying equally to all enterprise solution providers," the company said.

In the telecom industry, the term enterprise generally refers to company phones often tied to a corporate email account. RIM said it understands the new UAE policies would aim to avoid affecting "legitimate enterprise customers."

The TRA did not reply to a request for clarification Sunday.

RIM built its reputation on the security of its enterprise system, which routes encrypted data traffic through corporate computers typically stored abroad. That makes it extremely difficult to monitor.

It also sells BlackBerry devices to consumers who can access email through a less-secure system known as the BlackBerry Internet Service, which runs over the regular Internet.

"There is still some encryption. It is just not regarded as being as strong as the security on the BES," Reed said.

Other smartphone manufacturers, including Motorola Inc. and iPhone maker Apple Inc., are starting to win enterprise customers. But none has managed to unseat RIM in the UAE, where the BlackBerry remains the phone of choice among foreign professionals and affluent citizens alike.

The federation of just over 8 million people has at least 500,000 BlackBerry users.

The UAE's smartphone policies have been closely watched since last summer when it threatened to shut off BlackBerry messaging, email and Web browsing services partly because of security concerns. It backed off the plan in October.

Critics said the effort also aimed to keep a closer eye on political activism in the federation. Although the UAE has seen none of the widespread unrest roiling other parts of the Arab world, authorities have detained at least three activists calling for democratic reforms in recent days.

In 2009, the Emirates' leading state-run phone company, Etisalat, was caught instructing BlackBerry customers to download spy software that could allow outsiders to peer inside. It misled users by describing the software as a required service upgrade.