The Bush administration and congressional leaders launched a last-ditch campaign Friday to persuade world leaders attending a Sept. 14 U.N. summit to agree to broad management changes that would require greater accountability from U.N. officials, create a new ethics body and impose greater outside oversight over U.N. accounting methods.

The move came two days after former Federal Reserve chairman Paul A. Volcker, the head of the Independent Inquiry Committee, issued a scathing report on the mismanagement of the United Nations' $64 billion oil-for-food program with Iraq. The four-volume report, which runs more than 840 pages, provided a withering account of the failure of the international body -- including Secretary General Kofi Annan and the Security Council -- to properly administer the United Nations' largest humanitarian aid program.

At a news conference in Washington, Secretary of State Condoleezza Rice pressed the more than 170 world leaders who will attend the summit to agree to overhaul the U.N. bureaucracy to prevent such scandals. Rice also urged foreign governments to accept language in a summit document that condemns terrorism, promotes democracy and human rights and endorses free-market solutions to poverty.

"The United States is the largest single donor to the United Nations, and we owe the American taxpayers an accounting for the fact that its tax dollars are being used well," Rice told reporters. "Management reforms and secretariat reforms have got to be taken in the wake of the oil-for-food problem."

Asked if she continued to have confidence in Annan's leadership, Rice said, "We will continue to work with the secretary general, and we're confident that he will support the kinds of reforms that are needed to try and make sure that this sort of thing does not happen again."

Senate and House leaders, including Rep. Henry J. Hyde (R-Ill.), chairman of the House International Relations Committee, traveled to U.N. headquarters Friday to urge U.N. officials and ambassadors to undertake far-reaching changes.

Sen. Norm Coleman (R-Minn.), who has repeatedly called for Annan's resignation, had breakfast with U.S. Ambassador John R. Bolton and urged several foreign delegates, including the ambassadors of Russia, Japan and Britain, to strengthen oversight of U.N. operations. But he told reporters that he had no confidence Annan was in a position to impose changes required to restore public confidence in the organization.

Rep. Tom Lantos (D-Calif.), the ranking Democrat on the House International Relations Committee, said after a meeting with Annan that "calls for him to step down are misguided."

"He is the first to recognize the need for the fiscal and administrative reforms at the institution that Congress has called for," Lantos said.

The visits to New York came at a critical stage in U.N. negotiations on a final document to be agreed upon by heads of state and governments at the summit. The United States is facing intense resistance from scores of developing countries, who maintain that the U.S.-backed strategy would shift power over staffing and budgeting matters from the 191-member General Assembly to the secretary general.

"You cannot give all the powers to the secretary general," said Abdallah Baali, Algeria's U.N. ambassador. "The General Assembly has to keep its main prerogative, and the secretary general and all bodies should be accountable to the General Assembly."

U.N. delegates and officials are concerned that the stalemate over management reform and a simmering dispute between the United States and developing countries over the obligation of rich countries to dramatically increase foreign assistance could derail the negotiations. "This is a summit that hangs a little bit by a thread," said Annan's chief of staff, Mark Malloch Brown.

But Malloch Brown acknowledged that the U.S.-backed management reforms are necessary. "Nobody . . . could possibly read Paul Volcker's report and not conclude that structurally and systemically the organization is not up to the task entrusted to it," he said.

The Bush administration set off a diplomatic controversy last month when it called on foreign delegates to scrap language that urged wealthy countries to increase foreign assistance to 0.7 percent of their gross national products over the next decade. The aim was to meet a series of targets to drastically reduce rates of poverty, child mortality, HIV/AIDS, malaria and other diseases by 2015. Bolton introduced a compromise this week that would allow the inclusion of the targets, which are known as the Millennium Development Goals. But the United States, which opposes any numerical aid targets, is facing stiff opposition to the language.