Defense Secretary Rumsfeld told Fox News we can't afford to wait before dealing with threats from places like Iraq in an exclusive interview Monday, and warned that U.S. intelligence about Saddam Hussein's development of weapons of mass destruction may be years behind.

"Waiting to be attacked in a Pearl Harbor-like attack where several thousand people were killed results in several thousand people being killed," Rumsfeld said.

"Waiting to be attacked by someone who has been developing and has used weapons of mass destruction where you're looking at risking not several thousand of people but potentially several tens of thousands of people or hundreds of thousands of people is quite a different thing."

Rumsfeld, without referring to Saddam or Iraq by name, said it's time to act, and act now, adding the U.S. can't afford to let countries like Iraq get any closer to building chemical, biological or nuclear weapons.

"What evidence do we want? What do we need to think through as a people? And those are hard calls and I don't suggest they're easy at all," he said.

The Bush administration accuses Iraq of supporting terrorism and of rebuilding its banned weapons of mass destruction program. Many U.S. allies are resisting the push to oust the Iraqi president, arguing that an invasion cannot be justified without firm proof that Iraq is developing nuclear, chemical and biological weapons.

Lawrence Eagleburger, secretary of state under the first President Bush, told Fox News Sunday he did not believe a regime change in Iraq is "legitimate policy at this stage, unless the president can demonstrate to all of us that Saddam has his finger on a nuclear, biological or chemical trigger and he's about to use it."

But if intelligence bears that out and "Bush gets up and tells us all that that is what the intelligence shows us, I'll believe him. ... But I need to know — we all need to know, I think — what the purpose is, why is it that we have to do it now," he said.

Some fellow Republicans have in recent days strongly counseled Bush against military action.

Brent Scowcroft, national security adviser under Bush's father and President Ford, wrote in the Wall Street Journal last week: "An attack on Iraq at this time would seriously jeopardize, if not destroy, the global counterterrorist campaign we have undertaken."

In Congress, there is growing unease about the wisdom of taking pre-emptive military action against Iraq without just cause.

Sen. Richard Lugar, R-Ind., said support from American allies was crucial.

"We need to have our NATO allies. This is going to require heavy lifting," Lugar, a senior member of the Senate Foreign Relations Committee, said on NBC's Meet the Press. "Unless we plan this carefully, we're likely to destabilize other countries in the Middle East."

President Bush has said he has no timetable for deciding on a military strike or "for any of our policies in regard to Iraq." A decision may not come this year. He has pledged to consult with Congress and U.S. allies.

In his interview with Fox News, Rumsfeld gave what amounts to a rebuttal to some of the arguments currently being heard that there should be no early military action against Saddam's Iraqi regime.

"The people who argued have to ask themselves how they are going to feel at that point where another event occurs and it's not a conventional event but an unconventional event, and ask themselves the question, 'Was it right to have wanted additional evidence or additional time, or another U.N. resolution?'"

"It is always easier for a country, think of the prelude to World War II, think of all the countries that said, 'Well, we don't have enough evidence.' I mean Meine Kampf had been written, Hitler indicated what he had intended to do," Rumsfeld said. "Maybe he won't attack, maybe he won't do this or that. Well, there were millions of people dead because of the miscalculations had he been stopped early as he might have been done at minimal cost, minimal cost in lives, but no that wasn't done."

A White House aide said Sunday that Bush will clearly explain to Americans his decision to try to remove Saddam from power if he orders military action against Iraq.

"President Bush also understands if we go forward, if he decides that we need to take action to minimize the threat that he now poses, that he will do so in a way that will clearly be articulated to the American people, clearly articulated our friends and allies," the president's communications director, Dan Bartlett, said.

"And you'll find, because of the abysmal record of Saddam Hussein and the threat that he causes in the region, and to us as well, that we will have support."

Vice President Dick Cheney was a late addition to the participation list for the military planning summit Bush is convening Wednesday at his Texas ranch, where he is vacationing.

Cheney, reportedly hawkish on military action against Saddam, will join Rumsfeld, Chairman of the Joint Chiefs of Staff Gen. Richard Myers and others at the meeting. White House spokeswoman Claire Buchan said the session is not meant as a war-planning huddle on Iraq, but as a chance to update plans for military transformation, missile defense and the Pentagon budget.

Bush has said he will make up his mind "based upon the latest intelligence, and how best to protect our own country plus our friends and allies."

Congressional hearings this month examined various ways to achieve the U.S. government's stated policy of seeking a regime change in Baghdad, and a steady stream of news reports has suggested the administration is actively reviewing various war plans.

The president, who is vacationing at his Texas ranch, planned weekend meetings with his national security adviser, Condoleezza Rice. On Wednesday, Rumsfeld visits for a meeting that aides said would focus on plans for missile defense and the Pentagon budget.

The Associated Press contributed to this report.

Bret Baier currently serves as anchor of Fox News Channel's "Special Report with Bret Baier" (weeknights 6-7PM/ET), the top-rated cable news program in its timeslot. Based in Washington, D.C., he joined the network in 1998 as the first reporter in the Atlanta bureau. Click here for more information on Bret Baier