Defense Secretary Leon Panetta warned Congress on Tuesday that the $450 billion-plus in budget cuts he needs to make will hit them where it hurts — in their home districts.

To find the required savings, Panetta said the Pentagon will need to slice procurement programs, which would include pet projects and weapons systems made in manufacturing plants that provide precious jobs.

The former Democratic congressman from California said he hopes to find as much as $60 billion of the savings through efficiencies. But the bulk of the cuts, he said, will affect personnel and spending on military equipment, ships and aircraft.

"To accomplish this will require that we navigate through some very perilous political waters. There are serious dangers ahead and very little margin for error," Panetta said in a speech at the Woodrow Wilson International Center for Scholars, a nonpartisan think tank.

"In this fiscal environment, every program, every contract, every facility will be scrutinized for savings — savings that won't reduce readiness or our ability to perform essential missions."

Panetta challenged Congress to be "a responsible partner in supporting a strong defense strategy that may not always include their favorite base or their favorite weapons system."

Although the Pentagon is committed to cutting more than $450 billion in projected spending over 10 years, the reductions could reach double that amount.

This summer's deficit reduction agreement in Congress set up a special bipartisan committee to come up with $1.5 trillion in government savings. If it fails, or Congress rejects its proposals, automatic cuts of $1.2 trillion would begin in the 2013 budget year, with half coming from defense.

While the budget cuts will mean a smaller, but more agile military for the 21st Century, Panetta added that he will not let go of the Pentagon's long-held vision that the military must be able to possibly fight two simultaneous conflicts.

Military leaders as recently as Monday said that the budget calls will force cuts in the size of the force, and possibly in the number of Army brigades. Such cuts, said Gen. Raymond Odierno, Army chief of staff, will mean that the military won't be able to fight two conventional wars at the same time.

Speaking to reporters, Odierno noted that battling wars in Iraq and Afghanistan at the same time over the past decade forced the U.S. to bolster the size of the Army to meet the deployment demands. Shrinking the force to pre-war levels, he said, will mean the Army will not be big enough to handle two simultaneous conflicts.

The Army now includes about 570,000 soldiers, but the plan is to cut that total by nearly 50,000 by 2016.