Security firm McAfee warns a growing number of states across the world are preparing for potential cyber wars with other nations.
The United States continues to receive cyber attacks against computer networks from numerous sources overseas, though other nations also are becoming worried about the cyber capabilities of other nations. China, for example, said its defense ministry computer network has been attacked more than 2 million times since launching a few months ago.
"There are at least five countries known to be arming themselves for this kind of conflict," McAfee Europe analyst Greg Day told the BBC. "To go to physical war requires billions of dollars. To go to cyber war most people can easily find the resources that could be used in these kinds of attacks."