A major service outage afflicted users of the popular, addictive BlackBerry smart phones across the US and Canada.
Officials with AT&T Inc and Verizon Wireless said BlackBerry maker Research in Motion Ltd told them customers of all wireless carriers were affected.
It was not immediately clear how many of the 12 million worldwide BlackBerry subscribers had problems, as some users reported being able to access their service normally on Monday afternoon.
But Garth Turner, a member of the Canadian Parliament, said during a caucus meeting that the incident -- the second widespread disruption in 10 months -- was having a big impact.
"Everyone's in crisis because they're all picking away at their BlackBerrys and nothing's happening," Turner said.
"It's almost like cutting the phone cables or a total collapse in telegraph lines a century ago. It just isolates people in a way that's quite phenomenal," he said.
Bell Canada spokesman Jason Laszlo said the majority of its BlackBerry customers were affected by the service cut.
The BlackBerry service, which lets users check e-mail and access other data services on their handheld devices, has become a lifeline for many business executives and is increasingly popular among consumers with models like the BlackBerry Pearl.
In a statement, Research in Motion said the "service interruption" had resulted in "intermittent service delays for BlackBerry subscribers in North America."
The company said voice and text messaging services were not affected.
Research in Motion later said data service was restored around 6:30pm, about three hours after the outage began.
"No messages were lost and message queues began to be cleared after normal service levels were restored," the company said, apologizing to customers for the inconvenience.
There was no word on what caused the outage.
Major disruptions have been rare but often provoke an angry backlash against the Waterloo, Ontario-based Research in Motion because of its typically lengthy silences about the cause and because it eventually only provides cryptic, jargon-laden explanations.
When the BlackBerry service suffered a major outage in April, the company remained silent about the cause for two days.