WASHINGTON (AP) _ During the last two weeks, the Pentagon's unclassified computer networks have been subjected to ``fairly heavy cyber attacks,'' the military's number two civilian official said today.

``It was the most organized and systematic'' attack the Pentagon has seen to date,'' said John Hamre, deputy secretary of defense.

Hamre told defense reporters at a breakfast meeting that the event had ``all the appearances of a game'' and apparently was perpetrated by ``a small number of individuals.''

The deputy defense secretary said he was constrained from divulging too many details about the attacks because the military was working in cooperation with the Justice Department in pursuing potential criminal activity.

The offical said the attacks did not appear to be connected with the ongoing crisis involving Iraq.

He said the attacks appear to be directed at unclassified information, such as personnel records or payroll matters.

``Our classified networks were intact and not penetrated,'' he said.

He desribed the attacks as ``widepsread and modestly sophisticated.''

``During the last two weeks, the department experienced fairly heavy cyber attacks,'' Hamre said. He said the apparent hackers attempted to enter networks handled by all the military service branches.

``All the services had penetration to some degree,'' the official said.

He said the department has been attempting in recent years to update its defenses against such attacks but that more must be done.

``We have to do a good deal more in this area,'' he said.

Hamre said that the attacks appeared to be occuring at a time when a ``hacker contest'' was going on. But he did not say where such an event originated or offer a further explanation.