Research In Motion Ltd. said Wednesday that email service has been restored for "most" BlackBerry users after a disruption affected millions of accounts throughout North America.

"Root cause is currently under review, but service for most customers was restored overnight and RIM is closely monitoring systems in order to maintain normal service levels,'' the company said in a press release. "Email delivery was delayed or intermittent during the service interruption."

The technical problems, which were first reported around 8 p.m. EDT Tuesday, halted email traffic and access to the Internet on many of the devices.

Some users in Montreal and Waterloo said they weren't affected by the interruption.

But in Ottawa, Canadian politicians were lost without their highly addictive devices.

"We all lost our data when we were in the House of Commons last night. The sound of BlackBerrys being thrown against the desk was deafening for a while,'' Liberal MP Garth Turner told The Canadian Press.

"Because it has become the de facto channel of communications around this place, it actually impacts on the government of Canada and the work of the whole House of Commons.''

Phone service on the devices was not interrupted by the incident.

RIM criticisms

Jesse Hirsh, a technology industry watcher for Openflows Networks told CP that the incident demonstrates a lack of preparedness on the part of RIM.

"This certainly suggests that this was the type of catastrophic failure that exceeded their contingency plans," said Hirsh.

"Certainly customers and shareholders should ask after today whether their contingency plans were sufficient. Guaranteed they had redundant systems that allowed for a minor outage. This suggests something went horribly wrong.''

He said RIM has two network operation centres that handle the North American network. Since one is intended to work as a backup, Hirsch suggested that both of them went down.

"This is definitely a proprietary approach that they've taken which is not the industry norm,'' he said.

Hirsch said most companies like IBM and Google use the Internet instead of their own private servers -- lessening the effect from any technical crashes.

"The Internet has to go down to affect them in such a way. Because the Internet is distributed so largely it just doesn't happen any more."

Officials at RIM were unavailable to comment.

According to RIM's website, their total worldwide BlackBerry subscriber account base is approximately eight million.

In the U.S., about one million U.S. federal government and emergency workers use the devices.

RIM's customer support centre can be reached at 1-877-255-2377.

With files from The Canadian Press