Updated

America is at greater risk of a nuclear attack from terrorists because of the Bush administration's "single-minded focus on Iraq," Sen. Edward M. Kennedy (search) said.

In remarks prepared for delivery Tuesday, Kennedy, D-Mass., said North Korea (search) and Iran (search) have continued unchecked with their nuclear buildups while the United States preoccupies itself with Iraq (search).

"Instead of leading the world against the real threat of Iran's nuclear program, the president chose to lead America alone into the quicksand to counter the mirage of a threat in Iraq," Kennedy said in the remarks, prepared for a speech at the Carnegie Endowment for International Peace (search).

He said the administration's efforts to rid Iraq of a nuclear program it didn't have not only has destroyed U.S. credibility around the world, but has made Al Qaeda (search) terrorists more determined to launch a nuclear attack on America.

Kennedy said the United States would be better off under the leadership of Democrat John Kerry (search), who "has pledged to make preventing nuclear terrorism an absolute priority."

The remarks come as the International Atomic Energy Agency (search) is investigating nearly 20 years of covert nuclear activity by Iran. Tehran maintains its program is meant to generate electricity, but the United States claims it is a weapons program.

President Bush (search), who recently indicated a willingness to work more closely with France and Germany on nonproliferation issues, has labeled Iran part of an "axis of evil" with North Korea and prewar Iraq.

But Kennedy said the administration's unilateralism has caused a serious setback in nonproliferation policies. And he said Bush has compounded that neglect by pursuing research into a new type of nuclear weapon, called "bunker busters." The Senate last week rejected an effort to strip funding for the administration's research into mini-nukes.

"It is incredibly dangerous in this day and age to have a president who is so obviously resistant, uncomfortable and inept in working with other nations," Kennedy said. "Their approach to nuclear issues is erratic, unrealistic and irresponsible."

Kennedy noted Kerry's recent pledge to appoint a Cabinet-level official to oversee nuclear terrorism issues, and would speed up the lock-down of nuclear weapons materials.