Delays in the renovation of the United Nations headquarters, caused chiefly by the United States, are adding $225,000 a day to the project's costs, a U.N. official said Monday.

The United States is the lone holdout on the committee that must approve the next $100 million needed to proceed with the estimated $1.6 billion renovation, said Fritz Reuter, the U.N. official overseeing the program.

The projected cost of the project was good up through April 1. Every subsequent day of delay adds an estimated $225,000 — $3.8 million so far, he said.

U.S. Ambassador John Bolton said the United States only wants to grant approval for some $23.5 million because the General Assembly needs to agree on how to proceed with the project.

There has been no formal General Assembly agreement on a comprehensive renovation plan.

"We, the United States, think $23.5 million is a lot of money and we think it should carry a pretty good distance until we can have decisions by the General Assembly on other critical questions like what strategy the organization wants to follow," Bolton said.

Reuter and the top U.N. official in charge of the renovation said there was widespread agreement in the General Assembly on a plan that would empty out and renovate sections of the U.N. in phases. The United States would shoulder about 22 percent of the cost.

Reuter, an American, said the entire project, scheduled to be finished in 2014, could be delayed by years and cost far more if it is not approved immediately.

"It may be irreparably harmed if they don't have approval in the next week or so," Reuter said.

The United Nations has described the need for the renovation as extremely urgent. The U.N.'s glass-and-steel headquarters building on New York's East Side has not seen a major overhaul in its 60-year existence and now violates safety and fire codes. The building is packed with asbestos, has no sprinkler system and leaks about a quarter of its heating.

"We have reached a point in time where the building continues to deteriorate and we have a great deal of member consensus with the exception of the United States," Reuter said.

U.N. officials have looked at ways to renovate the Secretariat Building for several years, but the project has become embroiled in political squabbling.

Members of Congress especially have subjected the U.N. to strong criticism after the emergence of allegations of sexual abuse by peacekeepers and claims of corruption in the Iraq oil-for-food program. Several U.S. lawmakers have questioned whether the renovation plan is sound and cost-efficient.