The Obama administration says it will propose to Congress that U.S. ground forces be cut by 100,000 as part of nearly $500 billion in defense budget cuts during the next decade — but experts say the impact will be more muted than it might seem.

U.S. Defense Secretary Leon Panetta told reporters at the Pentagon Thursday that the administration will request a 2013 defense budget of $525 billion. That is $6 billion less than the request for the current fiscal year, which ends September 30.

But expert Ralph Cossa, head of the research group Pacific Forum, says the proposed cuts are reductions in spending projections, not in current spending.

Cossa says the cuts mean the budget would increase less, year to year, than previously planned.

Panetta said the plan is to increase the Pentagon budget to $567 billion by 2017.

Panetta said Thursday the defense department is also asking for an additional $88 billion for overseas operations to maintain support for troops in Afghanistan. The plan also includes a shift in focus to the Asia Pacific region and the Middle East.

Cossa of the Pacific Forum says the most significant cut will be in the number of ground forces, but adds that some of that reduction will likely be done through attrition, as service members retire or return to civilian life.

The Defense Department's announcement marks the start of this year's annual budget debate. The White House is expected to send its national budget plan to Congress in mid-February.

President Barack Obama unveiled the new strategic plan for the military earlier this month.

Congress and the Obama administration battled all last year over the federal budget and national debt. Republicans in Congress have opposed White House efforts to raise revenue in addition, and said the administration's proposed budget cuts were insufficient. However, many Republicans support deeper cuts in domestic programs rather than the military.