The ongoing war in Iraq (search) cost about $4 billion in September, spiked to $7 billion in October and hit just under $3 billion in November, the Pentagon said Wednesday in its latest report on how much the military operation costs.

That amounted to roughly $14 billion spent on U.S. military operations in Iraq over the three-month period late last year, the latest figures available, said Dov Zakheim, the Pentagon's chief financial official.

He said analysts were trying to determine why the costs spiked in October.

Officials previously had said the occupation of Iraq is costing $1 billion a week.

Zakheim also sought to allay concerns, expressed by top military chiefs to a congressional committee Tuesday, that the Pentagon would run out of money to finance the efforts.

The Iraq war and occupation, along with the ongoing operations in Afghanistan, are being paid for through supplemental spending bills that are approved by Congress outside of the regular budget process.

Already, Congress has approved $166 billion for those operations. The Pentagon has said it does not expect the Bush administration to seek another spending bill until January 2005, but the chiefs of the Army, Air Force (search) and Marine Corps (search) suggested Tuesday that money will run out by the end of September.

Zakheim said Wednesday that the military can fill the gap by borrowing money from other operations and maintenance accounts. This causes some repairs and maintenance work to be delayed, but Zakheim said this would not lead to permanent problems if a supplemental spending bill were approved by the following spring.

Why wait? Zakheim said the Pentagon wanted to see how events in Iraq unfold this year before deciding how much money it will need.

He denied the suggestion that the Bush administration was waiting until after the November elections to prevent the cost from becoming a political issue.