US government agencies have staged a simulated cyber attack on the country's power grid and other critical infrastructure to test Internet security measures and emergency preparedness.
The Department of Homeland Security (DHS) said on Friday in a statement that the exercise, dubbed "Cyber Storm," set out scenarios in which a "large-scale cyber incident" threatened the energy, IT, telecommunications and transportation sectors.
The DHS said 115 public, private and international agencies took part, including the departments of defense, state, justice, treasury, transportation, the Central Intelligence Agency and the National Security Agency.
IT companies such as Microsoft, Cisco Systems, Intel and Symantec also reportedly took part in the simulation, while representatives from the American Red Cross and other governments also participated.
The exercise had been originally scheduled for November but was postponed due to relief efforts related to Hurricane Katrina, which struck the US southern coast in August.
Some security experts have criticized President George W. Bush's administration as being ill-prepared for a potential cyber attack on sensitive networks.
DHS officials said the exercise would improve coordination between government agencies and the private sector.
"Cyber security is critical to protecting our nation's infrastructure because information systems connect so many aspects of our economy and society," George Foresman, DHS undersecretary for preparedness, said in a statement.
"'Cyber Storm' provides an excellent opportunity to enhance our nation's cyber preparedness and better manage risk," he said.