The officials said Defense Department planners are pegging the cost of the expected war at $60 billion to $95 billion. The long-term expense of occupying and rebuilding Iraq, as well as providing post-war humanitarian relief to as many as 2 million refugees, would be added to those costs, resulting in a marked increase in the $300 billion budget deficit the administration had projected for each of the next two years.

Until now, administration officials have provided only vague estimates of the cost of a war with Iraq. President Bush’s aides have said the only benchmark they could offer was the cost of the 1991 Gulf War, which was $61.1 billion, excluding reconstruction costs, or $82.5 billion in current dollars.

Five weeks ago, Defense Secretary Donald Rumsfeld told reporters that the administration was estimating the cost of a possible war at “under $50 billion.” Now, several officials said they are working with an estimate of $80 billion just for the Pentagon, plus foreign aid and other expenses. The new figures provide a measure of vindication for Bush’s former economic adviser, Lawrence Lindsey, who put the figure at $100 billion to $200 billion last fall, only to have other administration officials ridicule his estimate as excessive.

Bush met Tuesday with Rumsfeld and the White House budget director, Mitchell E. Daniels Jr., to discuss the matter. A Republican official called the estimate “dollar-rattling by the Pentagon” and said Bush will work to reduce the number.

Officials said the Office of Management and Budget, which Daniels heads, has been working on war estimates for at least five months. The scenarios being considered include such specific provisions as rebuilding 2,500 Iraqi schools, if necessary. With diplomacy continuing, administration spokespeople said that Bush has made no final decisions and that any specific figures were speculative.

White House officials still expect a speedy war, with estimates ranging from one to six weeks. But with deployments nearing their crest and final planning underway, the expected tab has risen. One reason, administration officials said, is that other countries in the region are following Turkey’s lead and demanding more US aid to cover their possible war-related costs. One official said the United States will be asked to increase assistance to Israel, Jordan, Egypt, Pakistan and perhaps other countries.

Military analysts said many of the costs are unknowable, such as possible decontamination requirements if Iraqi President Saddam Hussein launched chemical or biological weapons. “There could be massive, incalculable costs associated with Saddam lashing out against other countries, such as Israel, or pursuing a scorched-earth policy against his own people,” said Daniel Goure, a vice president at the Lexington Institute, a defense-oriented think tank.

About 80 percent of the 1991 Gulf War’s cost was borne by US allies. Administration officials said they expect the United States to pay most of the cost of a war in Iraq, although they would expect other countries to help with building a democratic Iraq after a war.

A senior administration official said more than two dozen countries — out of 191 UN member states — have agreed to provide assistance, including troops, expertise, political support or donations to humanitarian groups.

Rumsfeld told Congress early this month that the Pentagon had spent $2.1 billion so far on the buildup.

Administration officials had considered sending a supplemental budget request to Congress before an invasion to cover such expenses as the shelters, food and medicine for refugees that have been shipped to four countries in the Gulf region so the supplies would be ready for delivery right behind the military.

Now, officials say that when hostilities began, Bush would send Congress a request that included both Pentagon costs and about one year of resources for humanitarian and reconstruction agencies.