Research In Motion, the Canadian company that makes the BlackBerry smartphones, says service has been fully restored after a three-day outage, Associated Press news agency reported.

Mike Lazaridis, the co-CEO of the company, told reporters on Thursday that the backlog of messages that had clogged systems since Monday has been cleared up.

The outage started with a failure in Research in Motion Ltd's European data centre, and cascaded across the world as a back-up did not work either.

Millions of BlackBerry users around the world faced outage of email, messaging and internet services for three days.

Earlier on Thursday, the company had pledged to eventually deliver all delayed email and instant messages to customers in the five continents affected by the outage.

"You've depended on us for reliable, real-time communications, and right now were letting you down," it said had in a statement on its website and Facebook page.

Emails and messages from other regions to Europe had piled up in RIM's systems in the rest of the world, like letters clogging a mailbox.

That caused the outages in the US and Asia, David Yach, RIM's chief technology officer for software, said.

Unlike other mobile phone makers, RIM handles email and messaging traffic to and from its phones. That allows it to provide services that other phones lack, optimise data service and provide top-class security.

But when it encounters a problem, a large share of the 70 million BlackBerry subscribers worldwide can be affected all at once. BlackBerry outages tend to occur several times a year, but they usually last for less than a day.

Source: Agencies