More senior Pentagon officials are likely to step down in the coming days in the wake of Defense Secretary Donald Rumsfeld's announced departure, Pentagon officials told FOX News on Thursday.

Meanwhile, at Kansas State University, Rumsfeld said it was the "highest honor in my life" to serve as defense secretary. He also joked about the timing of the resignation announcement, one day before the long-planned speech for the Landon Lecture Series.

"I hope all of you appreciate how I have managed so skillfully public affairs for this event. I wanted to put the Landon Lecture on the map, so I did my best," Rumsfeld said to laughter from the audience.

Asked afterward what grade he would give himself as head of the Defense Department, Rumsfeld said he'd "let history decide that."

Among those expected to hand in resignation letters alongside Rumsfeld's is the Pentagon's top intelligence official, Under Secretary of Defense for Intelligence Steve Cambone, a close Rumsfeld associate and a key architect in planning for the Iraq war and the War on Terror.

Cambone is the first person to hold the post of intelligence under secretary, and in doing so helped the Pentagon step up its own intelligence gathering assets, a role traditionally overseen by the CIA. The new system led to turf battles between the two agencies in recent years.

A spokesman for Cambone would not speculate on whether the under secretary plans to stay after Rumsfeld resigns but said he knows of no change in his plans right now.

Another official said to be almost certain to leave is the Pentagon's chief financial officer, Under Secretary of Defense (Comptroller) and Chief Financial Officer Tina Jonas, who is the top manager overseeing the Pentagon's more than $400 billion military budget.

After years of scaling down the Defense Department in the 1990s, Congress began hiking the budget after the Sept. 11, 2001 terror attacks. The additional funding aimed to enable the U.S. to address growing challenges to national security.

In his speech on those challenges, Rumsfeld warned that "in the first war of the 21st century, we face an enemy that in many ways is unlike any our country has ever faced."

"We are engaged in a new and unfamiliar war that is, even today, not yet well understood. ... It's a struggle that will require all of us — our country, our government, our military and the American people — to think and act differently than we have in other conflicts," he said.

The White House announced Rumsfeld's departure on Wednesday, the day after Democrats won the majority in the next House of Representatives and appeared ready to take control of the Senate. On Thursday, Democrat Jim Webb beat incumbent Sen. George Allen in the Senate race for Virginia, officially giving Democrats control of the Senate.

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The defense secretary had been widely criticized by Democrats for what they say was his inability to foresee problems that would emerge after the liberation of Iraq from dictator Saddam Hussein. House Minority Leader Nancy Pelosi, set to become speaker in the next Congress, said the first step toward a new direction in Iraq should be Rumsfeld's departure.

Among the outspoken critics of the Bush administration, and Rumsfeld in particular, is Rep. John Murtha, D-Pa., himself a Vietnam War veteran. Murtha, who is in competition to become House majority leader, the second in command in the House, released a statement Thursday saying the military had lost confidence in Rumsfeld.

"It was absolutely necessary to bring in a fresh face," Murtha said of President Bush's decision to drop Rumsfeld.

But Murtha, who supports immediate redeployment of U.S. troops to the outskirts of Iraq, said he is not optimistic that a change in defense secretary will mean a change in policy.

"I was disappointed to hear the same old rhetoric coming from the president. He did not speak about a change of policy in Iraq. Changing the secretary does not change the policy, and the policy is set by the White House. We need a change in Iraq that is based on redeployment because that is what is best for America," Murtha said.

In the question-and-answer session with the audience after his speech, Rumsfeld fielded questions about criticism he faced and what kind of advice he would give to his successor. He seemed stumped when a uniformed reserve cadet asked how the secretary continued his daily life when faced with strong public criticism.

"My goodness. Those personal questions are hard — I guess the answer is that I feel so fortunate to have been able to participate and serve at important times in our country's history, and to do it with people like that," he said, motioning to his questioner.

Asked what the next defense secretary should do to try to bring peace to Iraq, Rumsfeld said he believed that the initial phase of the war, which he referred to as major combat operations, was "enormously successful," but "in phase two of this, it has not been going well enough or fast enough." President Bush declared major combat operations over in May 2003.

He said that the war in Iraq and the War on Terror are much like the Cold War was, a long and poorly defined fight that nevertheless is critical.

"Quite honestly, our country does not have experience attempting to impose control and our will over vicious, violent extremists that don't have armies, don't have navies, don't have air forces and operate in the shadows. It is a totally different circumstance," Rumsfeld said.

He said that the administration and military leaders will need to continue to make adjustments, but "if we have the perseverance and the resolve, we will end up seeing the Iraqi people ultimately take control over their country, govern their country, provide security for their country, and that is our hope and our prayer."

In announcing the secretary's resignation, Bush said he is nominating Robert Gates, a veteran of the CIA under President George H.W. Bush, to lead the Pentagon. Though closely tied to the Bush family, Gates is considered by many to be an agent of change.

After meeting Thursday with his Cabinet — minus Rumsfeld — Bush spoke briefly to reporters in the Rose Garden, and said Rumsfeld would stay on until Gates is confirmed.

"I'm deeply grateful to Don for his service to our country," Bush added.

Gates' confirmation hearings are expected the week of Dec. 4 with a final vote sometime before Dec. 31. Senate Armed Services Committee Chairman John Warner, R-Va., has also scheduled a lengthy hearing next week on Iraq policy that will include testimony from U.S. Central Command chief Gen. John Abizaid, CIA Director Gen. Michael Hayden and other top intelligence and foreign policy officials.

Gates awill have to pass through Warner's committee before a final vote by the full Senate.

Rep. Jane Harman, currently ranking minority on the House Intelligence Committee, said Gates would be a good fit to run the Department of Defense because of his intelligence background.

"He will respect the role of civilian intelligence agencies, including the CIA," Harman, D-Calif., said.

FOX News' Nick Simeone, Trish Turner and Greg Simmons contributed to this report.