The top U.S. general dropped into this volatile city Sunday to hear what was on the minds of Marines doing battle daily with a resilient and deadly insurgency.

Some of what he heard sounded like a sign of creeping doubt — not about the Marines' mission but about the wider purpose it is supposed to be serving as the U.S. war death count tops 2,600.

On his first visit to Fallujah as chairman of the Joint Chiefs of Staff, Marine Gen. Peter Pace stood before 1,300 troops — mostly Marines — and assured them that the American public supports them. And he predicted that Americans would continue to support the war.

"I think sometimes when you are out here at the tip of the spear, you wonder what's going on back in the United States and do you all still have the support of your fellow citizens," Pace said. "The answer is, yes, you do."

CountryWatch: Iraq

Public support for the troops doesn't extend to the Iraq war itself, however. More than half, 58 percent, said in a Newsweek poll out this weekend that the United States is losing ground in Iraq and opposition to the war has been growing.

During his meeting with the troops, the general also took questions.

How much more time, one Marine asked, should the Iraqi government be given to achieve the political unity necessary to stabilize the country?

"I guess they have as long as it takes," Pace replied, quickly adding, "Which is not forever."

Pace argued that setting a deadline by which the United States would withdraw its support would risk pushing the Iraqis into political decisions that are unviable. On the other hand, he said, "You do not want to leave it open ended."

Another Marine wanted to know if U.S. troops would stay in Iraq in the event of an all-out civil war. Pace repeated what he told a Senate committee last week: a civil war is possible, but not expected. He did not say what the United States would do if it actually happened.

Another asked what the United States would do if the Iraqi government did not support extending the U.N. resolution that authorizes the presence of American and other foreign troops in Iraq. Pace said the Iraqis already have said they favor extending the U.S. mandate, which expires in December.

One Marine wound up his question about the pace of U.S. troop deployments to Iraq by asking, "Is the war coming to an end?"

Pace didn't answer directly. He said Pentagon officials and military leaders are trying to keep enough troops in Iraq to achieve the mission of training Iraqi troops to take over the security mission, while avoiding having so many that it creates an Iraqi dependency.

There are now about 133,000 U.S. troops in Iraq.

At each stop on Pace's two-day visit to Iraq, which included Baghdad and Mosul as well as Fallujah, he thanked troops for their service and assured them that the American public still supports them.

Pace did not explicitly mention the political debate in Washington over when to withdraw from Iraq, but the senior commander of U.S. forces in western Iraq, Maj. Gen. Richard Zilmer, said in an interview Sunday that he is concerned about the effects of that debate.

Asked about the tenor of some of the questions put to Pace by Marines who seemed to harbor doubts about the long-term viability of the U.S. military mission, Zilmer said he is confident that virtually every Marine here is satisfied that their work is noble and just.

"But they are not immune to the discussions they see in public communications," Zilmer said. "Like all of us, they want to be assured that what we're doing is the right thing for the nation. Watching the Iraqi national government develop here has not been easy."

Zilmer noted the calls by some in Congress for a U.S. troop withdrawal to begin this year.

"That plays back here," he said. "People hear that. It does create the question: Is there the national commitment behind what we're doing over here?"