A U.S. proposal to delay approval of the United Nations operating budget has sparked a sharp debate over the course of U.N. reform. Secretary-General Kofi Annan cancelled a trip to Asia as the debate heated up.

Secretary-general Annan warned Friday that the world body could face a financial crunch if the General Assembly fails to adopt a full budget for the next two-year period.

Washington's U.N. Ambassador John Bolton has suggested approving a partial budget until the membership of the world body agrees to a series of U.S. backed reforms. Mr. Annan called the proposal unworkable. "This doesn't work for the United Nations. We are an organization of member states, and we live on contributions made by our member states," he said.

Speaking to a gathering of U.N. staff, the secretary-general rejected the idea of a linkage between the mission of the world body and the need for reform. He said he had cancelled a scheduled two-week Asia trip in hopes of heading off a budget crisis.

"The business of the U.N. is not reform. The business of the UN is carrying out the mandates of the General Assembly and the Security Council have given us, so that business must continue. And we should not take any initiative that not only risks the reform, but also the ongoing activities, and that's one of the reasons I decided to stay here and work with the member states to ensure that we do get the budget we need," he said.

The influential New York Times also weighed in sharply Friday against Ambassador Bolton's proposal. In a lead editorial titled "Blocking Reform at the U.N." the newspaper said the threat to withhold approval of the full two-year budget is "likely to be counterproductive". It accused the envoy of being "all muscle and no diplomacy".

Ambassador Bolton fired back Friday, and was joined by several influential colleagues in insisting that reform must be the paramount objective. He charged that the U.S. position had been distorted by critics, and said his limited budget plan would ensure that reform measures are funded. "The United States has never said we would hold the budget up. And what we proposed in order not to disrupt the work of the United Nations was an interim budget of three-four months, during which time the members of the General Assembly could consider its recommendations on reform," he said.

Representatives of other large contributor countries expressed support for Ambassador Bolton's goal, if not his tactics. Ambassador Kenzo Oshima of Japan, which together with the United States pays more than 40 percent of the U.N. budget, said he shares American concerns.

British envoy Emir Jones-Parry said while the European Union opposes any formal linkage between reform and the budget, he is sympathetic to Ambassador Bolton's objective.

"I have a lot of sympathy for what he's trying to do, which is to try and end up with a budget, when its put in place, which reflects the realities of what we've agreed," he said.

The General Assembly is scheduled to get down to hard work on reform and budget talks next week. Assembly President Jan Eliasson has set a December 20 deadline for agreement, and diplomats are expecting a flurry of negotiating activity in the week before the end-of-year holidays.