The United Nations Security Council voted unanimously today to approve a new resolution that endorses a U.S. transfer of sovereignty to an Iraqi interim government and authorizes foreign troops to provide security for at least a year with Iraqi consent.

The resolution passed 15-0 after the United States made several last-minute concessions to incorporate demands by France and Russia, which had insisted on giving the Iraqi government more explicit authority to ensure it exercised genuine sovereignty after the scheduled transfer of political power on June 30.

The vote represents "a vivid demonstration of broad international support" for a democratic Iraq, said John D. Negroponte, the U.S. ambassador to the United Nations, after the council approved the resolution.

"This resolution makes clear that Iraq's sovereignty will be undiluted and that the government of Iraq will have the sovereign authority to request and to decline assistance, including in the security sector," Negroponte said. "The government of Iraq will have the final say on the presence of the multinational force."

He called on other nations to "join those already helping the talented people of Iraq" by contributing assistance to the country.

Under the resolution, the mandate of the "multinational force" in Iraq -- a coalition made up mostly of U.S. troops -- will be reviewed by the Security Council "at the request of the government of Iraq or 12 months from the date of this resolution." It says the mandate will expire at the end of a political process that culminates with a constitutionally elected government by Dec. 31, 2005.

But the resolution also makes clear that the Security Council "will terminate this mandate earlier if requested by the government of Iraq."

The resolution recognizes that Iraqi security forces are under the control of the Iraqi government. And it gives the government a say on security issues, including the launching of "sensitive offensive operations" by the multinational force, such as the April offensive against insurgents in Fallujah. But it stops short of granting the Iraqi government any sort of veto power over these operations, as France and Germany had sought.

The document incorporates letters from the interim Iraqi prime minister, Ayad Allawi, and Secretary of State Colin L. Powell. Allawi's letter says that until Iraq is able to ensure its own security, it needs the multinational force in Iraq.

Powell's letter says the multinational force stands ready to counter security threats from violent insurgent groups by carrying out "combat operations against members of these groups, internment where this is necessary . . . and the continued search for and security of weapons that threaten Iraq's security."

In meeting these responsibilities, "we will act in full recognition of and respect for Iraqi sovereignty," Powell's letter says.

In accordance with the annexed letters, the resolution says, the multinational force will "have the authority to take all necessary measures" to maintain security and stability in Iraq.

Speaking before the vote, President Bush said he was "delighted" by the prospect of a new resolution. "There were some who said we'd never get one," he told reporters at the Group of Eight summit meeting at Sea Island, Ga. "I think this is a very important moment. . . ."

Bush said during a photo opportunity with Japanese Prime Minister Junichiro Koizumi that the members of the Security Council "understand that a free Iraq will serve as a catalyst for change in the broader Middle East, which is an important part of winning the war on terror."

He said he expects other nations "to contribute as they see fit" to the multinational force, but that ultimately the key to long-term security in Iraq lies in training Iraqi troops to take over the job themselves.

France, Germany, Russia and Canada -- accounting for half the membership in the Group of Eight -- have said publicly that they do not intend to send troops to Iraq. The other four Group of Eight members -- the United States, Italy, Japan and Britain -- currently maintain troops in Iraq, including 135,000 supplied by the United States.

Powell said before the vote that the international community was "coming together again to support the Iraqi people. . . ." The resolution "makes clear what the role of the coalition force is with respect to the interim Iraqi government, and you'll see that the interim Iraqi government is the sovereign," Powell told reporters at a meeting in Washington with Iraq's interim president, Ghazi Yawar.

Yawar, who is representing Iraq at the Group of Eight summit, said his country was "counting on our friends in the U.N. and international community to help us in having our sovereignty," as well as in "preserving law and order until we establish our security forces." He dismissed a question about the prospect of U.S. and Iraqi disagreement on sensitive military operations, saying, "We cannot afford to be pessimistic. We are confident that this cooperation . . . will be very positive and beneficial for the Iraqi nation."

The passage of the resolution hands the Bush administration a pivotal victory as it ends the 14-month administration of Iraq by the U.S.-led Coalition Provisional Authority, headed by L. Paul Bremer. The Security Council's approval also stood in stark contrast to the divisions and diplomatic disarray at the world body when the United States failed last year to win U.N. backing for a resolution authorizing military intervention in Iraq.

The resolution is critical for Iraq as well, because it bestows international legitimacy on the new government 22 days before the official transfer of power.

With the U.N. vote today, Negroponte said, Iraq will soon begin "a new phase in the political history, the full restoration of sovereignty and authority over Iraq's own affairs."

Staff writer Robin Wright contributed to this report.