"It is too early to determine root cause at this time, but RIM does have a team addressing this issue in order to define the problem and prevent it in the future," the company said in a statement.
The BlackBerry service, which lets users check e-mail and access other data, has become a lifeline for many business executives and is increasingly popular among consumers with smart phones like the BlackBerry Pearl.
Outages have been rare in the BlackBerry's nine-year history, but when they do hit, subscribers who have become addicted to the gadgets are quick to unleash their fury.
"I'm mad - it's enough already," said a frustrated Stuart Gold, who said he gets 1,000 e-mails a day as director of field marketing for Web analytics company Omniture Inc.
Gold, who worked most of Monday on a laptop while traveling, plans to ask his company to buy him a backup smart phone from a rival like Palm Inc., which makes the Treo, in case BlackBerry service goes on the blink again.
"I don't know what happened, I don't care what happened. They need to save their excuses for someone who cares," Gold said.
RIM has 12 million subscribers worldwide and has deals with scores of wireless carriers to offer the BlackBerry service around the world.
The company did not say how many were affected, though officials with AT&T Inc. and Verizon Wireless said RIM told them the outage hit customers of all wireless carriers. Bell Canada spokesman Jason Laszlo said the majority of its BlackBerry customers were affected.
On Monday, users described frantic moments of tapping away at disabled machines before realizing an outage had zapped their service.
"Everyone's in crisis because they're all picking away at their BlackBerrys and nothing's happening," Garth Turner, a member of the Canadian Parliament, said during a caucus meeting. "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."
The last major BlackBerry outage struck in April, when a minor software upgrade crashed the system, triggering complaints from always-on users all the way up to the White House and Canada's Parliament. A smaller disruption occurred in September, when a software glitch stanched the flow of e-mails.
The previous BlackBerry outages have prompted angry backlashes against RIM because of the company's lengthy silences about what caused them and the cryptic and jargon-laden explanations that eventually emerge.
RIM waited two days after the April outage before telling customers what happened.
The last major failures were nearly two years before that. The company angered users by waiting hours before confirming the problem, then issuing a confusing technological description of what happened.