The U.N. Security Council moved beyond its bitter fight over the U.S.-led invasion of Iraq to deliver unanimous support Tuesday to a new Iraqi government and a vow to help steer the country toward democratic elections next year.

By a vote of 15 to 0, the council endorsed a resumption of Iraqi control over the nation's political and economic affairs for the first time since the fall of Saddam Hussein. The U.S.-dominated military occupation of Iraq will end formally on June 30, although 160,000 foreign soldiers will remain to battle insurgents.

The vote on the latest Iraq resolution opened the door to a fresh, if uncertain, stage of the Bush administration's project to remake Iraq. After months of insisting on control, the White House calculated that Iraqi leaders backed by a more united international community could turn back the militant opposition that has beset the occupation.

President Bush, preparing to welcome leaders of the world's most industrialized economies to the Group of Eight summit in Sea Island, Ga., hailed the vote as a "catalyst for change." He called it "a very important moment in seeing that our objective is achieved."

In a spirit far different from that of 18 months ago, leaders from Russia, Britain and Germany followed with hopeful words after reaching compromises on a resolution designed to strengthen the interim government and show skeptical Iraqis that the United States will no longer dominate Iraqi politics.

"Without any exaggeration, I would state that it is a major step forward," said Russian President Vladimir Putin, who opposed the invasion of Iraq. But he added, "Naturally, it will take quite a long time before the adoption of the document will have any impact on the real change on the ground in Iraq."

British Prime Minister Tony Blair, Bush's closest ally in the coalition that deposed Hussein, said: "We all now want to put divisions of the past behind us and unite behind the vision of a modern and stable Iraq that can be a force for good, not just for Iraqis but for the whole region and thus the whole world."

The Bush administration considers the Security Council vote a victory, particularly after failing to win U.N. support for the March 2003 invasion. It took five versions and a battery of U.S. concessions to make the vote unanimous -- and to produce it on the American schedule, before the G-8 summit began Tuesday night.

With each version, the resolution delivered more assurances of Iraqi authority over Iraqi affairs and more precise details about how the U.S.-controlled occupation would end. Compared with recent diplomatic battles, this one went smoothly, diplomats on all sides said.

The final version backs a measure of sovereignty for Iraq that gives its leaders the authority to make political decisions and control the economy, including oil-industry revenue that foreigners have managed for more than a decade. Contracts signed by the U.S.-run Coalition Provisional Authority will be honored, the resolution states.

An interim government headed by Ayad Allawi, a secular Shiite once supported by the CIA, will command Iraq's security forces and will have the right to order the exit of foreign troops, although he said he does not intend to do so.

On the most delicate issue, the United States preserved the authority to wage offensive military operations as American commanders see fit. The Bush administration promised "close coordination" and "full partnership" with the Iraqis, who may opt to keep Iraqi forces out of such operations.

"Iraq's sovereignty will be undiluted," U.S. Ambassador John D. Negroponte told the Security Council after the vote. "The government of Iraq will have the sovereign authority to request and to decline assistance, including in the security sector."

Speaking in Washington, where he met with Secretary of State Colin L. Powell, interim Iraqi President Ghazi Yawar said Iraqis "cannot afford to be pessimistic" despite the violence that has slowed reconstruction. He said he is "counting on our friends in the U.N. and international community to help us."

Yawar said he feels confident about the role of U.S. forces in Iraq and their pledge to consult on sensitive military operations.

"We will be working together," he said. "These people are in our country to help us against bad elements. They are not going to be part of doing negative or having negative impact on the . . . law-abiding Iraqi citizens."

It remains unclear how the resolution will translate into additional concrete support from other nations -- a fervent desire of the Bush administration, long criticized for not giving other countries more substantive roles earlier. Top U.S. officials have conceded that additional foreign security forces are likely to remain unattainable until the violence diminishes.

Diplomats said Tuesday's vote resulted from a newfound flexibility on the part of a Bush administration that had steadfastly insisted on doing things its own way in Iraq.

Heraldo Munoz, Chile's U.N. ambassador, credited the administration with making "a U-turn on the U.N. role."

A senior State Department official said the administration took a different tack this time. The White House was prepared to give away more than it was previously.

"To some extent, the way we got this resolution was different from the past," the official said. "It's now a question of what the Iraqis want and no longer a debate about the United States."

Before and after the war, the Bush administration had largely sidelined the United Nations on political decisions in Iraq despite White House assurances that the world body would have a "vital role." In recent months, as American forces found themselves again at war and taking heavy casualties, U.S. authorities emphasized the need for U.N. help in creating a political solution.

The interim government is intended to hold power until Iraqis choose their own leadership, a task the United Nations is now committed to overseeing. Diplomats said it will be crucial to provide security for U.N. workers. They said much of the rest will be up to the Iraqis.

"We want to send a message to the Iraqis," one council diplomat said. "This is opening a new chapter, with your own fate in your hands. Please get it done."

Wright reported from Washington. Staff writer Glenn Kessler contributed to this report from Georgia.