(CNN) -- Millions of BlackBerry users remained without service on Wednesday as a three-day network outage spread to North America, causing massive frustrations for people who rely on these smartphones for business and personal communications.
"BlackBerry subscribers in the Americas may be experiencing intermittent service delays this morning," Research in Motion, maker of BlackBerry smartphones, said in a statement. "We are working to resolve the situation as quickly as possible and we apologize to our customers for any inconvenience. We will provide a further update as soon as more information is available."
The outage now impacts people on nearly every continent, according to the company's statements.
An "extremely critical issue" on the BlackBerry network caused the outage, Stephen Bates, RIM's managing director in the U.K., told CNN's Richard Quest. He added: "We're putting all of our focus with all of our engineers and all of our network specialists on trying to understand the nature of why this backup system didn't work as it should have ..."
The service outage started on Monday with customers in the Middle East, Europe and Africa, before spreading to South America and Asia on Tuesday. On Wednesday morning it appeared to hit the United States and Canada. The outage appears primarily to affect text messaging and Internet access from the mobile phones, not necessarily their ability to place calls.
No customer e-mails have been completely lost, and they will be delivered eventually, RIM said in a press conference on Wednesday afternoon, according to CNNMoney's Julianne Pepitone.
In a statement released Tuesday, the company said the "messaging and browsing delays being experienced by BlackBerry users in Europe, the Middle East, Africa, India, Brazil, Chile and Argentina were caused by a core switch failure within RIM's infrastructure. Although the system is designed to failover to a back-up switch, the failover did not function as previously tested."
The company said it is working "around the clock" to fix the problem.
"A large backlog of data was generated and we are now working to clear that backlog and restore normal service as quickly as possible," the Tuesday statement said. "We apologize for any inconvenience and we will continue to keep you informed."
There are about 70 million BlackBerry users worldwide. RIM has not commented on how many users are affected, but reports suggest the number of users without some sort of service has climbed into the millions.
BlackBerry users, many of whom use the devices primarily for business purposes, were angered by the outage.
Many people took to Twitter to both complain about lost productivity and to make light of the situation.
"COME ONNNN. Sort it out #blackberry. This is ridiculous in this day and age," a Twitter user named @Suzy__G wrote.
"OK, this #Blackberry business is now SERIOUSLY pissing me off," CNN's Piers Morgan tweeted.
Later, he said: "One positive of the #Blackberry crisis - my personal trainer can't get hold of me. #OrderingBurgers."
"#DearBlackberry I can't work, I can't study, please, please come back from that coma!" @marianaae wrote.
"What did the one #Blackberry user say to the other?..........nothing....," said another Twitter user, @giselewaymes.
"And iPhone users everywhere smile smugly and search for the 'I Told You So' app," wrote another.
A website called isblackberrystillbroken.com popped up to track developments.
People who visited the site on Wednesday afternoon were greeted with a red screen and a giant word: "Yes."
This is not the first time RIM has faced a major service outage.
"I have been an analyst for 25 years and have watched RIM wrestle with this same outage problem time after time. Every few years we get pinched by yet another major problem," tech analyst Jeff Kagan said in a statement.
This outage, however, comes at a particularly bad time for RIM, since it faces increasing competition in the smarpthone market, Kagan says. Apple's iPhone and phones on the Google Android operating system have been gaining ground, and the new iPhone 4S goes on sale Friday.
The tech blog Electronista wrote:
"RIM's outage is now one of its largest in recent memory and is now edging even closer to the iPhone 4S launch than before, leading to a possible temptation for those already looking to upgrade their phones. Commentary on Twitter has shifted gradually from frustrated patience to open anger and has led some to remark that they're now likely to switch to the iPhone, Android, or another platform."