U.S. and Australian officials will announce Thursday that a mutual defense treaty will be expanded to include cooperation on cyber warfare.

The announcement, at a meeting of the two countries' foreign and defense ministers in San Francisco, marks the first time Washington has established a cyber warfare partnership outside of NATO.

Speaking to reporters Wednesday on his flight to the West Coast city, Defense Secretary Leon Panetta stressed his belief that electronic processing and communications are “the battlefield of the future.”

He said the United States will not only have to work hard to defend against cyber attacks, but also be aggressive in developing its own attack capability.

He said the best way to accomplish that is by working together with allies.

Panetta did not identify any potential cyber warfare combatants in the Asia-Pacific region, where Australia is the United States closest ally. However China and North Korea have both been moving rapidly to develop their own cyber warfare capabilities.