Democrat John Kerry (search) faulted President Bush for a unilateral approach toward Iraq that has created greater dangers for the U.S. military, but the presidential candidate was heckled Wednesday for failing to back the immediate withdrawal of American forces.

"We shouldn't only be tough, we have to be smart. And there's a smarter way to accomplish this mission than this president is pursuing," the four-term Massachusetts senator told reporters at City College of New York (search) following an education event.

Kerry backed the 2002 congressional resolution authorizing the president to use force in Iraq, but since then has been harshly critical of Bush's foreign policy. Maintaining his support for the military operation while challenging the Republican incumbent — and appealing to the Democratic base — has proven to be a tough dilemma for Kerry, evident by Wednesday's events.

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During a question-and-answer session with the audience, retired college professor Walter Daum angrily accused Kerry of backing an imperialist policy in Iraq and called on the candidate to demand the immediate withdrawal of U.S. troops.

"You voted for this," Daum shouted. As he spoke, a group stood silently and unfurled a large sign that read, "Kerry take a stand: Troops out now."

"You're not listening," an exasperated Kerry said at one point.

Later, speaking with reporters, Kerry dismissed the notion of withdrawing American forces and indicated that if U.S. generals and other senior officials say they need more troops, he would back such a move. Bush at his news conference Tuesday night said he would support an increase in the military presence in Iraq.

"I think the vast majority of the American people understand that it's important to not just cut and run," Kerry said. "I don't believe in a cut-and-run philosophy."

During his day at the college's Harlem campus, Kerry promoted his plan to give a free college education to students who agree to public service by ending a $13 billion windfall that banks earn for issuing government-backed student loans.

He held a series of fund-raisers in the city, collecting $6.5 million for his campaign and $2.4 million for the Democratic National Committee (searchat a New York hotel and nightclub. In the first quarter of the year, Kerry raised a Democratic record of some $50 million.

The influx of money will allow Kerry to increase dramatically his campaign advertising as early as next week. The ad buy is part of a broader effort to flesh out his biography and spell out his message for Americans who know little about the senator six months before the election. It also will dovetail with the candidate's public schedule and coordinated activities by surrogates and supporters in various states.

But the increasing violence in Iraq and Bush's response remained front and center for the president's Democratic rival, who argued for a full partnership with the United Nations, stressed the importance of stability in Iraq and complained about Bush's strategy creating an undue burden for Americans.

"The president made clear what we all share, which is a sense that the United States of America is going to be resolute and tough and make certain that we accomplish our mission," Kerry said.

Other nations share the U.S. goal of stability in Iraq and, if elected president, Kerry said he would use his powers of persuasion to convince them that their interests demand they share in the effort.

"Our soldiers are bearing the brunt of this operation," Kerry said. "Our military is to some degree overextended. American soldiers are bearing the huge majority, the lion's share of this."

Republicans rejected the criticism, with Bush's re-election campaign chairman Marc Racicot calling Kerry's comments "a political attack that is very, very seriously undermining our efforts in Iraq and in the war on terror."

In a conference call with reporters, Racicot said Kerry simply blames America for provoking the attacks in Iraq without offering a competing vision that addresses the war on terrorism.

"To say something like we need to get the target off the backs of our troops, I mean for God's sakes, if that could be any more extravagantly irresponsible I don't know how," Racicot said.