President Bush addressed a raucous crowd of U.S. Marines at Camp Lejeune, N.C., Thursday, thanking them and their families for their role in Operation Iraqi Freedom.

"There's no finer sight than to see 12,000 Marines … unless you happen to be a member of the Iraqi Republican Guard," Bush said, getting thunderous applause and yelling from the audience.

"America has entered a fierce struggle," he continued, but "we will not stop until Iraq is free. The course is set. We're on the advance. Our destination is Baghdad and we will accept nothing less than complete and final victory."

Twenty-five thousand Marines from Camp Lejeune are serving in Iraq right now. The president addressed 12,000 Marines remaining on base and 8,000 family members at the outdoor venue, Goettge Memorial Field, which was filled with stadium-style seating practically overnight.

Throngs of people packed the field and overflow crowds lined the sidewalks of the base. Flags bearing yellow ribbons fluttered from lamp posts.

Bush hailed the military men and women who contributed to the daring rescue of prisoner of war Pfc. Jessica Lynch from an Iraqi hospital this week. Throughout the speech, he frequently had to pause because of the deafening applause and cheering from the crowd.

In recent days, questions about the wisdom of the Pentagon's battle plan have subsided somewhat, giving way to reports of huge routs of Republican Guards by coalition forwards advancing toward Baghdad and images of Iraqis welcoming U.S. forces in Najaf and fleeing Baghdad in huge numbers to surrender to coalition troops.

Bush warned that those in Saddam Hussein's regime who aren't turning themselves in to coalition forces or laying down their arms are in for a rude awakening, especially since U.S. ground forces are now on the outskirts of Baghdad, with some Special Operations forces actually working inside the capital.

"The regime in Iraq is now learning that we keep our word," Bush said. "Free nations will not sit and wait, waiting for enemies to plot another Sept. 11, this time perhaps with chemical, biological or nuclear terror."

The White House and its allies -- such as Britain and Spain -- say Saddam still holds weapons of mass destruction that were supposed to be given up to U.N. weapons inspectors. No such weapons have yet been found, but items such as chemical suits and gas masks have.

And in yet another sign that coalition forces are making headway, Bush said Iraqi civilians are warming to allied troops securing their cities.

He said "Saddam's thugs" are shielding themselves on the battlefield with women and children, killing citizens who welcome coalition troops, threatening families of men who don't want to join the regime in battle and executing POWs. They are also concealing combat forces in civilian neighborhood structures such as schools, hospitals and mosques to maximize civilian casualties, he said.

But that all will be over soon, the president assured.

"A vice is closing and the days of a brutal regime are coming to an end," Bush promised.

"The Iraqi regime is terrorizing it's own citizens … these are war criminals and they will be treated as war criminals."

But Bush also made a point to say ousting Saddam is necessary for America's security, as is shoring up our own homeland defenses.

"We're applying the power of our country to secure our country," Bush said.

Joined on Air Force One by North Carolina Sens. John Edwards, a Democrat seeking the 2004 presidential nomination, and Elizabeth Dole, a Republican, Bush made the trip to their home state to speak to the Marines and their families, and then to share lunch with some of the troops.

He was also scheduled to spend time in private with five families of Marines killed in the fighting so far. Of the Marines serving from Camp Lejeune in Operation Iraqi Freedom, 13 have been killed and six are missing in action. A White House spokesman said the president wanted to spend time with "every soul in that room."

"Camp Lejeune has lost some good Marines … this is a battle of hardship for many military families," Bush told the crowds.

"We honor their service to America and we pray their families will feel God's comfort and grace," he said. "These are sacrifices of a high calling -- the defense of our nation."

Just as the U.S. military has a tradition to leave no soldier behind in battle, so the country has a motto of never forgetting those who die protecting it, the president said.

"Marines are in the thick of the battle. And what we've begun, we will finish."

The president has been getting daily war updates from Secretary of Defense Donald Rumsfeld and National Security Adviser Condoleezza Rice. The president is said to be very proud of the military and resolved to see the war through to victory.

Brig. Gen. Vincent Brooks reported Thursday from U.S. Central Command in Doha, Qatar, that troops have "enjoyed very good freedom of action" after destroying several enemy installations and force postures. Military leaders are debating whether to charge the Iraqi capital or wait for reinforcements and give Iraqis a chance to overthrow Saddam Hussein's regime on their own.

Brooks would not say when any move on Baghdad may occur, but Fleischer warned that while progress is being made in the fight, expectations of Americans must be "calibrated to the reality."

Thursday's was Bush's third straight visit to a military installation since the war began last month. Of the three, Camp Lejeune has been hit hardest by combat deaths.

Fox News' Molly Henneberg and Liza Porteus contributed to this report.