A technical failure in Europe is suspected of causing a huge backlog of messages worldwide for BlackBerry users, who have experienced three days of outages, Research In Motion said Wednesday.

RIM's chief technology officer, David Yach, said messages coming into Europe from Asia and the Americas to BlackBerry users got backed up and started affecting BlackBerry users globally.

Outages for RIM's instant messaging service, email and internet browsing started at the beginning of the week in Europe and spread to Canada and the U.S. on Wednesday while the company scrambled to restore service.

It's the biggest outage in years to hit the BlackBerry, which now has 70 million subscribers around the world.

Many Canadian BlackBerry users could get nothing more than a message on their screens that read, "Unable to connect to the selected mobile data service, please try again later."

Areas of South America, Africa and the Middle East, as well as Asian markets including Hong Kong, Japan, Singapore and India were also affected.

It's in overseas markets where RIM has had its fastest growth in the last two years.

Shares in the Waterloo, Ont.-based firm closed down more than three per cent Wednesday as investors worried that the problem would undermine the BlackBerry's reputation for reliability.

RIM shares fell 87 cents, or 3.46 per cent, to $24.27 on the Toronto Stock Exchange.

Yach told a media briefing that the firm was throttling traffic in order to "stabilize service" and clear the backlog. RIM promised that all messages will be delivered.

Yach said the company believes it has found the cause and has found no evidence of hacking.

The BlackBerry outage even reached Prime Minister Stephen Harper's office.

Andrew MacDougall, spokesman for the prime minister, took to social networking site Twitter and tweeted: "Am being impacted by RIM/Berry service outage — please call if you need to reach me."

On Tuesday, the firm announced the problems were caused by a core switch failure within the company's infrastructure. RIM said a transition to a backup switch did not function as tested, causing a large backlog of data.

Waterloo, Ont.-based Research In Motion says the problems that have plagued users of its BlackBerry smartphones worldwide were caused by a core switch failure within the company's infrastructure. (Associated Press)

"The resolution of this service issue is our No. 1 priority right now and we are working night and day to restore all BlackBerry services to normal levels," the company said in a statement Wednesday.

RIM also apologized.

"We are working to resolve the situation as quickly as possible and we apologize to our customers for any inconvenience," RIM said.

However, an apology didn't seem to be good enough for the government of Colombia, which reportedly asked RIM to compensate users affected by the glitches.

RIM's last outage was in December 2009 and it also experienced an outage in 2008.

"It's a huge embarrassment for a company that has built its reputation on notion of service and reliability and when all else fails your BlackBerry will still work," said Michael Gartenberg, director of research at U.S.-based Gartner Inc.

Apple's iPhone 4S, announced last week, is set to hit stores Friday.

Technology analyst Troy Crandall said he expects the outages to have more of an effect in the corporate market.

"That's the bread and butter still for RIM," said Crandall of Montreal-based MacDougall, MacDougall & MacTier. "It just kind of puts the thought in people's heads — might it be time for a switch?"

RIM earns revenue from both the sale of its smartphone devices and a monthly fee subscribers pay to use its secure email services and instant messaging capabilities, which means users switching to other phones could eat away at its profits.

With files from The Canadian Press