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Dozens of international leaders celebrated the 60th anniversary of the United Nations (search)' birth, but warned that the organization must institute significant reforms to remain an effective global peacekeeper.

The Bush administration signaled its discontent with the world body by sending a single representative to the commemoration. Delegate Sichan Siv (search), who represents the U.S. on the U.N. Economic and Social Council, did not speak at the anniversary celebration.

While officials gave emotional addresses about human rights and the organization's successes in forging global peace, speakers emphasized that the U.N. must restructure and redefine its goals to counter terrorist threats.

Several delegates said it would be a mistake for the U.S. to give up on the world body at a time when the U.N. is poised to institute major reforms.

"In today's world, no state can protect itself alone," said Mary Robinson, former U.N. high commissioner for human rights and president of Ireland, in a speech at Grace Cathedral. "A transparent and accountable United Nations is in the United States' interest. We know the U.N. needs reform, but it also needs resources."

Representatives gathered Sunday to celebrate the U.N.'s anniversary in the city where the global organization was signed into being. They were greeted at the Fairmont Hotel by volunteers wearing 1940s Red Cross uniforms and newsboys hawking mock papers from June 26, 1945, the day 50 member states signed the charter that established the world body, now based in New York City.

Delegates said the next few months will be crucial in revealing the United States' position toward the organization.

The U.S. has not had a delegate at the United Nations for five months. President Bush's nominee to the U.N., John R. Bolton (search), is locked in a confirmation battle with Senate Democrats. Concern about allegations of fraud in the U.N.'s Oil-For-Food program and the organization's inability to enforce its policies has fueled a backlash against the U.N. led by House Republicans.

While delegates discussed the Bolton nomination among themselves, the House of Representatives' vote last Friday to withhold dues until the U.N. implements reforms generated the most talk.

"You can't join a club and say you won't pay your dues but you want changes," U.N. Undersecretary-General Shashi Tharoor told The Associated Press. "The U.S. simply has to engage with other countries."

The Bush administration and legislative leaders have united behind a bipartisan task force to design the U.N.'s internal reforms. Former House speaker Newt Gingrich and former Senate Majority leader George Mitchell recently released a report that recommended the U.N. set up an independent auditing board and establish weighted votes on financial issues in favor of members who contribute more to the budget.

In September, the U.N. General Assembly will meet in New York to discuss the report and to institute change within the organization.