Fresh off his re-election victory, President Bush vowed the United States would not retreat from trying to spread democracy through the Middle East and would continue to pursue a no-holds-barred approach to Iraq and the War on Terror (search).

"I understand, in certain capitals and certain countries, those decisions were not popular," Bush said at his first post-election news conference Thursday. But he made no apologizes about the course he had set and said he would not back down.

Before flying to the presidential retreat at Camp David (search ) to rest after the grueling campaign, Bush took congratulatory calls from world leaders and met with his Cabinet to discuss his second term.

He said he had not made any decisions about personnel changes, although some turnover is almost inevitable in his Cabinet and White House staff.

"I haven't made any decisions on the Cabinet yet," nor about his top staff, Bush said. "The word 'burnout' is oftentimes used in Washington, and it's used for a reason, because people do burn out."

The first job to change hands could be that of attorney general, since John Ashcroft might leave even before the second term begins, senior aides said Thursday.

• Read more about the Cabinet shuffle here.

Others expected to leave — although maybe not immediately — include Secretary of State Colin Powell (search), Health and Human Services Secretary Tommy Thompson (search) and Transportation Secretary Norman Mineta (search).

FOX News has learned that Thompson has indicated to associates that he would leave early in Bush's second term.

"I'm proud of every person here — they've done a great job for the country and I've reminded them that even though an election just ended, we've still got work to do," Bush told reporters after the Cabinet meeting Thursday.

"I made it clear to them [the Cabinet] I was glad the election was over and reminded them that we're here for a reason," Bush said at the meeting. "They understand that it's such an honor to serve America, it's a privilege to sit around this table ... and do the nation's business."

As U.S. forces in Iraq mobilized for an all-out offensive against Fallujah and other Sunni militant strongholds, the president refused to say how much the war would cost or whether he planned to alter troop levels.

"I have yet to hear from our commanders on the ground that they need more troops," the president said.

Privately, senior Pentagon officials said it was possible that more U.S. forces could be deployed before January.

Two overnight raids in Fallujah destroyed barricades set up by guerrilla forces inside the city. But troops have not yet moved into the heart of the city.

U.S. military commanders believe the insurgents have used the past few months to booby-trap roads and set up potential ambushes using homemade bombs, which they said might slow down the assault but would not stop it.

The president on Thursday expressed determination to see the Iraq mission through.

"In order for Iraq to be a free country, those who are trying to stop the elections and stop a free society from emerging must be defeated," Bush said.

He vowed to work with the government of interim Prime Minister Ayad Allawi (search).

The president is expected to ask Congress early next year for up to $75 billion for Iraq, Afghanistan and operations against terrorism.

The White House said that with Bush's second-term victory and the planned Israeli withdrawal from the Gaza Strip, it sees a new opportunity to advance Mideast peace.

"I think it's very important for our friends the Israelis to have a peaceful Palestinian state living on their border," Bush said. "It's very important for the Palestinian people to have a peaceful, hopeful future."

Bush did not go as far as British Prime Minister Tony Blair in declaring that the Israeli-Palestinian conflict is the world's most important political challenge.

"I agree with him that the Middle East peace is a very important part of a peaceful world," said Bush. One factor in Mideast peace talks is Palestinian leader Yasser Arafat, whom a senior Palestinian official said was in a coma in a French hospital.

Bush reaffirmed his policy, enunciated in June 2002, of an independent Palestinian state existing at peace with Israel. The U.S.-backed plan for peace, known as the "road map," called for the new Palestinian state in 2005.

"My hope is that we'll make good progress," Bush said.

The president sees the war in Iraq as part of a drive to establish a stable democracy in the Middle East and create a model for the rest of the region.

"And I fully understand that that might rankle some, and be viewed by some as folly," Bush said. "I just strongly disagree with those who do not see the wisdom of trying to promote free societies around the world."

Bush said he'd reach out to countries around the globe, as well as organizations like the European Union and NATO, to help in the War on Terror and spread democracy; he stressed that these are issues that shouldn't be politicized.

"Every American has a stake in the outcome of this war — Republicans, Democrats and independents," the president said. "We have a solemn duty to protect the American people, and we will."

Bush is the first president in 68 years to have won re-election while his party gained seats in both the House and Senate. He said Americans have embraced his conservative agenda.

"I'll reach out to everyone who shares our goals," said Bush. A day earlier, he had promised to try to win over those who voted for his Democratic opponent.

"I've earned capital in this election — and I'm going to spend it for what I told the people I'd spend it on, which is — you've heard the agenda: Social Security and tax reform, moving this economy forward, education, fighting and winning the War on Terror," the president said.

FOX News' Steve Centanni and The Associated Press contributed to this report.