Computer network and security experts have said there is no evidence the power outage in the northeastern United States and Canada was related to the Blaster computer worm that began spreading on Monday.
Experts said Internet traffic appeared to be running smoothly as major websites, Internet backbone providers and web-hosting companies relied on back-up power.
"I have no thought that [the outage] is Blaster related," said Mr Alan Paller, research director at the SANS Institute in Bethesda, Maryland.
The worm targets Microsoft's Windows XP and Windows 2000 computers, infects and crashes them and spreads to other vulnerable machines.
Mr Paller said it is "highly unlikely" that the process control computers behind critical infrastructure like power in the United States would run on the Windows operating system.
"There is no information available at this time to indicate that the power outages in the northeast United States and Canada are related to intruder activity," said the Computer Emergency Reponse Team at Carnegie Mellon, in response to questions about the worm.
Spokesmen at AT&T's Global Network Operations Center and Cable & Wireless CW.L , carriers for large segments of Internet traffic worldwide, said their back-up systems had kicked in after the outage hit late afternoon.
Internet traffic should continue to be unaffected, said Lloyd Taylor, vice president of technology at Keynote Systems, a Web performance monitoring company."Generators can run for two to three days with fuel on site," he said.
Some internal corporate networks in the northeast were suffering, though. NETSolve, a remote network management outsourcer, said the internal networks went down from the power outage at up to 10 percent of its more than 1,000 customers, said Bob Kujawski, vice president of service delivery at NetSolve.