The Washington Times 
Sept 14, 2011
The general in charge of U.S. cyberwarfare forces said Tuesday that future computer-based combat likely will involve electronic strikes that cause widespread power outages and even physical destruction of thousand-ton machines.
Army Gen. Keith Alexander , commander of the new U.S. Cyber Command , also said that massive losses of private and public data in recent years to computer criminals and spies represent the largest theft in history.
Threats posed by cyber-attacks on computer networks and the Internet are escalating from large-scale theft of data and strikes designed to disrupt computer operations to more lethal attacks that destroy entire systems and physical equipment.
“That’s our concern about what’s coming in cyberspace – a destructive element,” Gen. Alexander , who is also the director of the National Security Agency , the electronic spying agency , said in a speech at a conference on cyberwarfare.
Gen. Alexander  said two cases illustrate what could happen in an attack.