WASHINGTON - President Barack Obama on Thursday announced a new defense strategy that he says will make U.S. military forces "leaner" in the coming years while still maintaining their global superiority.

In an unprecedented appearance before the press corps at the Pentagon, Obama unveiled the broad outlines of a plan that calls for a beefed-up military presence in the Asian-Pacific region and investment in NATO and other international partnerships to go along with U.S. troop withdrawals in Iraq and Afghanistan.

"The tide of war is receding," Obama said, "but the question that this strategy answers is what kind of military we will need after the long wars of the last decade are over."

The contours of the plan are not surprising, and follow Obama's highly public plan to shift military spending away from a combat-troop presence in the Middle East and toward intelligence gathering, surveillance and counter-terrorism efforts.

But as Obama prepares to announce specific plans to trim the growth in defense spending, he also is readying himself for criticism of his commitment to national security.

Republican presidential contenders question the Democratic president's national-security policies and are likely to go after his budget-cutting plans for the Pentagon.

Obama launched a preemptive strike Thursday with an argument that, with resources so scarce, Congress must streamline the military along with the rest of the government.

Under his plan, Obama said, the U.S. still will have a defense budget larger than those of the next 10 countries combined.

"Some will no doubt say the spending reductions are too big, others will say they're too small," Obama said. "But I would encourage all of us to remember what President Eisenhower once said, that each proposal must be weighed in the light of a broader consideration - the need to maintain balance in and among national programs."