The Pentagon will need an additional $12.3 billion through September to pay for wars in Iraq and Afghanistan and its worldwide effort against terrorism, congressional auditors estimate.

That is triple what Gen. Richard Myers (search), chairman of the Joint Chiefs of Staff (search), projected in April he would need to make it through September.

Lawmakers of both parties said at the time that his projection seemed too low, so the congressional projection issued Wednesday was no surprise.

Democrats quickly used it to criticize President Bush for underestimating the burden the wars — especially in Iraq — have thrust on taxpayers.

"He has grossly mismanaged the war on terrorism and the war in Iraq," said Mark Kitchens, deputy press secretary to Democratic presidential candidate Sen. John Kerry, D-Mass. Kitchens called the study "another example of how George W. Bush planned for best case scenarios and failed to prepare for the realities of war."

Rep. John Spratt (search), D-S.C., who requested the study, said it underlined "another in a long line of miscalculations" by Bush on Iraq.

At the White House, budget office spokesman Chad Kolton defended the president.

"When it comes to making decisions about resources for our men and women in uniform, the only thing that matters is ensuring they have what they need to get the job done," Kolton said.

The report was written by the Government Accountability Office, Congress' investigative arm formerly called the General Accounting Office.

Its release came a day before Congress was expected to approve a $417.5 billion defense bill for next year that includes $25 billion for military operations in Iraq and Afghanistan. That $25 billion will be available as soon as Bush signs the measure, but it is unclear that the administration will use any of that money until the fall.

After Congress provided $87 billion last November for Iraq and Afghanistan, the White House began this year insisting it would need no extra money until next year. Under congressional pressure, it requested $25 billion in May for use beginning next October, when the government's new budget year begins.

Rather than using the new $25 billion to plug any gaps, the Pentagon could try shifting money from other funds or delaying some expenditures. Democrats said they believed Bush would do that because spending part of the $25 billion would drive up this year's budget deficit, already expected to set a record in the $450 billion range.

"Ascribing all these other theories" about how Bush will handle a shortfall "have nothing to do with it whatsoever," Kolton said.

Pentagon spokeswoman Lt. Col. Rose-Ann Lynch said the Defense Department believes it has enough money for this year — if Congress gives it authority to transfer an extra $1.1 billion within its existing budget, which is roughly $400 billion.

She said defense officials have planned to use the $25 billion to cover operations from October through next March. Even so, she said department officials do not believe the report is necessarily wrong.

"We always said it was going to be tight," Lynch said.

House Budget Committee Democrats estimated that the Pentagon has $5 billion in unspent funds it can use to help plug the gap, still leaving it more than $7 billion short.

The GAO report found that most of the projected shortfall — $9.4 billion — would come from the Army, which is conducting the brunt of the operations in Iraq and Afghanistan. Of the rest, $1.4 billion would come from the Air Force, $1 billion from the Navy and $500 million from the Marines.

Most of the projected gap is for operations and maintenance items like the costs of transporting troops and refurbishing equipment.

To free up funds, the Army is planning to defer equipment repairs while the Air Force and Navy are trimming peacetime flying hours, the report said.

So far, Congress has provided $191 billion for Iraq and Afghanistan and global efforts against terror, including money to help rebuild those two countries.