The Defense Department will prepare three scenarios for war funding next year depending on how many U.S. troops, if any, will remain in Afghanistan, according to an internal Pentagon email obtained last week by Bloomberg News.

One estimate would take into account 10,000 U.S. troops stationed in the country, another would presume 5,000, and a third would imply no presence as of Jan. 1, 2015, according to the email labeled "for official use only."

The Pentagon earlier this year sent Congress a placeholder request of $79.4 billion for war operations in fiscal 2015, which begins Oct. 1. That request didn't include specifics. The Defense Department is developing the three more detailed war-funding budget estimates to present to the White House, according to the email.

“These assumptions are for budget planning purposes only,” said the email sent by John Roth, the Pentagon's deputy comptroller for programs and budgets. “They do not imply operational decisions or plans that have been or may be made.”

Todd Harrison, a defense-budget analyst for the nonpartisan Center for Strategic and Budgetary Assessments in Washington, said in an emailed statement that keeping 10,000 troops would cost about $25 billion a year and 5,000 would cost about $20 billion annually.

Afghan election

Much of the Pentagon's war request depends on the outcome of Afghanistan's presidential election and agreement on a security accord that would govern any U.S. troop presence in that country once most forces withdraw this year. Hamid Karzai, the departing president, has delayed signing the pact needed to keep some U.S. troops in the war-torn country beyond this year and secure billions of dollars in pledged aid funds.

Results counted so far in the Afghan vote held earlier this month indicate that candidates Abdullah Abdullah and Ashraf Ghani Ahmadzai will face each other in a runoff, which would further delay the signing of the security pact. Still, both Abdullah and Ghani have vowed to sign the agreement, calling it crucial for Afghanistan’s stability.

About 33,000 U.S. troops currently are stationed in Afghanistan. U.S. and NATO officials have been considering proposals to keep a combined force of 8,000 to 12,000 troops who would continue training Afghan forces for the next few years.

Legislation delayed

The absence of a specific war-funding request has complicated the approval of the annual defense bills. The U.S. House has no timetable for passing the 2015 Pentagon spending measure because of the lack of such a request, said Representative Rodney Frelinghuysen, a New Jersey Republican and chairman of the House Appropriations Defense Subcommittee.

An attachment to the Pentagon email says that the White House Office of Management and Budget plans to negotiate the final war funding “positions” with the Defense Department on May 23.

Asked today about the comptroller’s review, Army Colonel Steve Warren, a Pentagon spokesman, said “our budget planning is consistent with our contingency planning.”

“Budget doesn’t drive policy,” he said. “Policy will drive the budget so when the president has made his decision on troop numbers we will then be able to rapidly attach a dollar figure to that decision.”

Defense Department spending in Afghanistan through the first four months of this fiscal year has averaged $4 billion a month, according to the most current data, and $532.7 billion since the war began in October 2001.