Washington ? When war ends in Iraq, the Bush administration will give “extremely high priority” to halting a secret nuclear weapons program in neighboring Iran, a senior administration official said Monday.

John Bolton, the under secretary for arms control, joined National Security Adviser Condoleezza Rice in warning that the White House sees nuclear weapons programs in Iran and North Korea as imminent threats.

“The estimate we have of how close the Iranians are to production of nuclear weapons grows closer each day,” said Bolton, a leading hawk within the administration.

Both Bolton and Rice, in separate speeches to the annual conference of the American Israel Public Affairs Committee, suggested that the Bush administration viewed the toppling of Saddam Hussein in Iraq as an initial response to a series of threats. However, neither of them suggested that Washington is pondering military action elsewhere.

President Bush last year tagged Iraq, Iran and North Korea as an “axis of evil” that threatens world order, and the U.S.-led invasion of Iraq has unnerved Iran and North Korea.

Rice defended the Bush administration’s constant warnings that rogue regimes are acquiring even more lethal weapons.

“Sometimes people think we’re a little bit ‘the-sky-is-falling, the-sky-is-falling’ on these regimes that the president called the axis of evil,” Rice said. She added, however, that recent evidence shows that “they certainly belong” on the list.

Rice voiced frustration that the Vienna-based International Atomic Energy Agency (IAEA) hasn’t been more aggressive with Iran’s nuclear program and suggested the need for shaking up the way weapons monitoring programs function.

“Once we have a better atmosphere after Iraq, one of the things we’re going to have to look at is how the world gets itself better organized to deal with issues concerning weapons of mass destruction,” Rice said.

In a separate presentation, Bolton said Iran was seeking nuclear weapons “in a very comprehensive and sophisticated way.” A U.N. team of nuclear inspectors that visited Iran Feb. 21-22 found a series of centrifuges to enrich uranium, a process critical to making nuclear weapons material, he said.

“The IAEA was stunned by the sophistication of the Iranian effort,” Bolton said.

Bolton did not forecast when the administration believes Iran might be able to process fissile material for nuclear weapons, acknowledging that such estimates often prove inaccurate.

He said U.S. officials now view Iran and North Korea as equivalent threats, even amid evidence that North Korea may be only months from production of nuclear material for weapons.

“In the aftermath of Iraq, dealing with the Iranian nuclear weapons program will be of equal importance as dealing with the North Korean nuclear weapons program,” Bolton said.

Bolton said a series of complicated emerging nuclear weapons threats might present themselves “simultaneously” to the White House once the Iraq campaign is over. “This is going to be a substantial challenge,” he said.