President Obama has signed executive orders setting cyberwar guidelines for the Pentagon.

The orders spell out just how far military commanders can go in using cyberattacks and other computer-based operations against enemies and as part of routine espionage in other countries.

The orders also detail when the military must seek presidential approval for a specific cyber assault on an enemy and weave cyber capabilities into U.S. war fighting strategy, defense officials and cyber security experts told The Associated Press.

Officials said the guidelines are much like those that govern the use of other weapons of war, from nuclear bombs to missiles to secret surveillance.

Cyber attacks range from planting a computer virus to bringing down an enemy's electrical grid or defense network.

"You don't have to bomb them anymore. That's the new world," said James Lewis, cybersecurity expert at the Center for Strategic and International Studies.

Hackers have already breached U.S. military networks and weapons programs. Top government officials warn it's only a matter of time before terror groups learn how to launch cyber attacks.

"I've often said that there's a strong likelihood that the next Pearl Harbor that we confront could very well be a cyberattack that cripples our power systems, our grid, our security systems, our financial systems, our governmental systems," incoming Pentagon chief Leon Panetta recently told Congress.

The Pentagon is expected to announce its entire cyber strategy soon.