BBC NEWS | Technology | Windows worm numbers 'skyrocket'

'Right now, we're seeing hundreds of thousands of unique IP addresses connecting to the domains we've registered,' F-Secure's Toni Kovunen said in a statement.

'We can see them, but we can't disinfect them - that would be seen as unauthorised use.'

Microsoft says that the malware has infected computers in many different parts of the world, with machines in China, Brazil, Russia, and India having the highest number of victims.