The United States and its allies are winning some battles in the terrorism war but may be losing the broader struggle against Islamic extremism that is terrorism's source, Defense Secretary Donald Rumsfeld said Saturday.

The troubling unknown, he said, is whether the extremists -- whom he termed ''zealots and despots'' bent on destroying the global system of nation-states -- are turning out newly trained terrorists faster than the United States can capture or kill them.

''It's quite clear to me that we do not have a coherent approach to this,'' Rumsfeld said at an international security conference."