BlackBerry services improved in several regions including Europe, the Middle East and India on Thursday after three days of outages that have incensed users, the system's under-pressure owners said.

Canada-based Research In Motion (RIM) has blamed a backlog of emails from Europe for the glitches which have starved millions of users around the world of instant access to emails and messaging.

"From 6:00 am BST (British Summer Time, 0500 GMT) today, all services across Europe, the Middle East and Africa, as well as India, have been operating with significant improvement," a statement on BlackBerry's UK website said.

"We continue to monitor the situation 24/7 to ensure ongoing stability. Thank you for your patience."

RIM said on Wednesday that an initial technical failure had prompted a build-up of messages in its network, triggering a cascade of problems around the world that affected many of the firm's 70 million subscribers.

The problems spread to the United States on Wednesday.

"It is a backlog issue," RIM software vice president David Yach said, ruling out any rumours of sabotage or hacking for the problems that started on Monday and continued despite initial claims that the issue had been resolved.