A senior U.S. intelligence official also dismissed the administration's assertion that the threat of nuclear terrorism is growing.

"The threat has been there," the official said. "But there is no new intelligence."

The official said the administration appears to be inflating the danger in ways similar to what critics of the Bush administration charged with regard to Iraq: hyping intelligence to support its policies.

The official said one likely motivation for the administration's new emphasis on preventing nuclear terrorism is to further the president's goal of eliminating nuclear weapons. While the U.S. nuclear arsenal would be useful in retaliating against a sovereign state, it would be less so against a terrorist group. But if the latter is the world's major nuclear threat, the official explained, then the U.S. giving up its weapons seems less risky.