SOURCE

Washington - Hackers in several incidents broke into electrical utilities overseas

and demanded extortion payments before disrupting power

- in one case turning off the lights across multiple cities,

a senior CIA analyst told utility engineers at a trade conference.

All the break-ins occurred outside the United States, senior CIA analyst Tom Donohue said.

The US government believes some of the hackers

had the benefit of inside knowledge to cause the outages.

Donohue did not specify what countries were affected,

when the outages occurred or how long the outages lasted.

He said they happened in "several regions outside the United States."

"In at least one case, the disruption caused a power outage affecting multiple cities,"

Donohue said.

"We do not know who executed these attacks or why,

but all involved intrusions through the internet."

A spokesperson for the Central Intelligence Agency on Friday

declined to provide further details.

"The information that could be shared in a public setting was shared,"

said spokesman George Little.

"These comments were simply designed to highlight to the audience

the challenges posed by potential cyber intrusions."

Donohue spoke earlier this week at the Process Control Security Summit in New Orleans,

a gathering of engineers and security managers for energy and water utilities.

The Bush administration is increasingly worried about the little-understood risks

from hackers to the specialised electronic equipment that operates power,

water and chemical plants.

In a simulated test last year, the Homeland Security Department produced

a video showing commands quietly triggered by simulated hackers having

such a violent reaction that an enormous generator shudders

as it flies apart and belches black-and-white smoke.

The recorded demonstration, called the "Aurora Generator Test",

was conducted in March by government researchers investigating a dangerous vulnerability

in computers at US utility companies known as supervisory control and data acquisition systems.

The programming flaw was quietly fixed, and equipment makers urged utilities to take protective measures.