Army General Henry Shelton declined to specify how computers were used against Belgrade in the 11 week war, but told reporters, "You can assume we employed some of our systems."

"I'd rather not be specific about how we used it, to be frank. I don't want to divulge too much on this," he said.

Shelton made the comments as he flew back from a ceremony in Norfolk, Virginia, marking changes in responsibilities of the nine US unified military commands to address two perceived threats: information warfare and potential biological, chemical or nuclear attacks on US soil.

The reorganization puts the US Space Command in Colorado Springs, Colorado, in charge of coordinating the US military's information warfare effort.

The task of preparing the US military for potential chemical biological or nuclear attacks in the United States was assigned to the Norfolk-based the Joint Forces Command, which replaces the Atlantic Command.

"I don't think there's any question that as we look to the future that our information systems throughout America, and specifically within the Defense Department, will be more and more subject to attack if an adversary elected that as one of the asymmetric means of going against the United States," Shelton told reporters earlier in Norfolk.

He said a Joint Task Force for Computer Network Defense created by the Pentagon six months ago will be placed under the US Space Command, which already is a center of expertise in computers, communications and space assets such as satellites.

Initially the task force will concentrate on defending US information networks against cyber attacks, but a year from now plans call for adding a unit dedicated to developing an offensive information warfare capability, senior Pentagon officials said.

Potential targets range from computer-linked air defense systems to influencing an adversary's perception of events by manipulating computerized data.

Shelton said the use of such an offensive capability required a decision by President Bill Clinton.

But he said information warfare efforts already are underway within the military services and in at least two commands.

"What you have to do is coordinate all of this to make sure you're getting maximum leverage from it," he said.

"And that's where you call it information operations, as you pull it all together, as you move it in a coordinated, methodical manner to either influence their actions or deny them the ability to figure out what we're doing."

In similar fashion, a task force at Joint Forces Command in Norfolk will develop contingency plans for the military's response in the event of a biological, chemical or nuclear attack on US soil.

The Pentagon has moved gingerly into this area because US law prohibits the military from engaging in law enforcement activities inside the United States to safeguard civilian control.

But US officials are worried that an incident involving weapons of mass destruction would quickly overwhelm civilian authorities, giving them little alternative but to call upon the military for help.

US Defense Secretary William Cohen stressed, however, that even then the military would be confined to a supporting role.

"I believe the American people should be very concerned about the nature of the growing threat, and how the talent, expertise, the doctrines and training the military can be in support of (civilian authorities)," he said.

"This is not in any way to undermine civilian control of the military."