President Bush, speaking to U.S. troops in Iraq today ahead of Saturday's referendum on a new constitution, thanked them for "being a part of this global war" and vowed to press on until "total victory" over an enemy he described as ruthless and cold-blooded.

In a videoconference with 10 U.S. military personnel and one Iraqi soldier, Bush said the referendum vote must be protected to help defeat the "backward, dark philosophy" of the insurgents and lay "the foundation for peace."

"I want you to know that the mission you are on is vital to achieving peace and to protecting America," Bush said, addressing a large video screen in the Eisenhower Executive Office Building next to the White House. "And so I want to thank you for being a part of this global war. And Iraq is a part of the war, because the enemy understands that . . . a free Iraq will be a blow to their vision and their strategy of spreading dominance throughout the broader Middle East."

The White House apparently intended the event to be a question-and-answer session with the soldiers, as Bush, adopting a folksy, informal manner, sought both to assure them of popular support and draw them out about their activities in Iraq.

But the troops, who sat in three tiered rows at their base in Tikrit, the hometown of deposed Iraqi president Saddam Hussein, took turns giving what appeared to be prepared statements that were not necessarily related to the questions Bush was asking.

The message from the soldiers was essentially that Iraqi forces have been taking an increasing role in the fight against the insurgency and in preparations for the referendum.

The American soldiers who participated are members of Task Force Liberty. Led by the New York National Guard's 42nd Infantry Division, the unit includes two National Guard brigades from Tennessee and Idaho and two active-duty brigades from the Army's 3rd Infantry Division.

The White House, which initially had described the video teleconference as unscripted, appeared to be put on the defensive by a barrage of questions about the event. Before it began, reporters saw a Pentagon official come to the same podium Bush used and brief the soldiers about what to expect from the president.

White House spokesman Scott McClellan later told reporters the conference was "set up to highlight an important milestone in Iraq's history" and that the soldiers could "ask the president whatever they want." In fact, none of the soldiers asked Bush a question.

"Obviously, there's going to be some coordination going on when you're setting up an event like this," McClellan said. But he insisted that the soldiers were expressing "their own thoughts."

Asked if they "rehearsed" their statements, McClellan said, "Well, my understanding is that someone from the Department of Defense was talking to them ahead of time, but I don't know; I was with the president."

In his opening remarks to the troops, Bush said, "We're facing an enemy that is ruthless and cold-blooded, an enemy that actually has a philosophy, and the philosophy is so opposite of ours. It is the exact opposite of what America stands for."

"Part of their strategy . . . is to use the killing of innocent people to get the American government to pull you out of there before the mission is complete," Bush said. "I'm going to assure you this: that so long as I'm the president, we're never going to back down, we're never going to give in, we'll never accept anything less than total victory."

Bush told the troops, "You've got tremendous support here at home."

When Bush asked Capt. Brent Kennedy if he was confident about preparations for the referendum and how he felt operations were going, Kennedy handed the microphone to Capt. David Smith of Grand Rapids, Mich., who informed the president that the Iraqi army has been "conducting battalion- and brigade-size operations since April" and coordinating referendum preparations with other Iraqi security forces.

"Sir, we as coalition forces . . . have taken a supporting role only as they prepare to execute this referendum," Smith said.

Asked by Bush for an assessment of whether "the Iraqis want to fight, and are they capable of fighting," Smith handed off to Capt. Stephen N. Pratt, of Pocatello, Idaho, who described Iraqi participation in a "training model" for the referendum and predicted "a very successful and effective referendum vote."

Capt. David Williams of Los Angeles said voter registration was up 17 percent in north-central Iraq. He said his Iraqi counterpart in Tikrit informed him last week that local residents were "ready and eager to vote in this referendum."

Another officer, 1st Lt. Gregg A. Murphy of Tennessee, said Iraqi forces are far more involved now than during preparations for Iraq's elections in January.

"Back in January, when we were preparing for that election, we had to lead the way," Murphy said. "We set up the coordination, we made the plan. We're really happy to see, during the preparation for this one, sir, they're doing everything. They're making the plans, they're calling each other, they've got it laid out."

Bush, referring to Tikrit as "Saddam's old stomping grounds," observed that Iraqis "didn't get to vote too often when he was the leader there."

He said later, "I wish I could be there to see you face-to-face to thank you personally. Probably a little early for me to go to Tikrit, but one of these days perhaps the situation will be such that I'll be able to get back to Iraq to not only thank our troops, but to thank those brave Iraqis who are standing strong in the face of these foreign fighters and radicals that are trying to stop the march of freedom."

When Master Sgt. Corine Lombardo, of Scotia, N.Y., recalled Bush's visit to New York City following the Sept. 11, 2001, terrorist attacks and thanked him for recognizing her unit's role in rescue efforts, Bush sought to engage her in conversation. "Were you there when I came to New York?" he asked.

"Yes I was, Mr. President," said Lombardo, a public affairs officer in the 42nd Infantry Division.

"Yeah, I thought you looked familiar," Bush said, adding, "I probably look familiar to you, too."

Lombardo went on to praise "a tremendous increase in the capabilities and the confidences of our Iraqi security force partners," and Bush told her, "I appreciate you bringing that up, Sergeant Major."

Asked if he had something to say, an Iraqi soldier identified during the videoconference only as "Sergeant Major Akeel" of the 5th Iraqi army division, answered, "Good morning, Mr. President. Thank you for everything, sir. Thank you very much for everything. . . . I like you."

Bush chuckled and said, "Well, I appreciate that."

The White House later named the soldier as Sgt. Maj. Akeel Shaker Nassir, senior noncommissioned officer in charge of the Iraqi army training facility in Tikrit.

Bush concluded the session by thanking the troops "for being so courageous and for stepping up when the United States of America needed you." He said, "And when you get back to the States, you know, if I'm hanging around, come by and say hello."