Defense Secretary Robert M. Gates said Monday that the Pentagon will cut thousands of jobs, including a substantial chunk of its private contractors and a major military command based in Norfolk, as part of an ongoing effort to streamline its operations and to stave off political pressure to slash defense spending in the years ahead.

Gates said he will recommend that President Obama dismantle the U.S. Joint Forces Command, which employs about 2,800 military and civilian personnel as well as 3,300 contractors, most of them in southeastern Virginia. He also said he will terminate two other Pentagon agencies, impose a 10 percent cut in intelligence advisory contracts and slim down what he called a "top-heavy hierarchy" by thinning the ranks of admirals and generals by at least 50 positions.

The reduction in funding for contract employees -- by 10 percent annually over three years -- excludes those in war zones.

(Post Investigation: Top Secret America)

Although the moves will save an unspecified amount of money, defense officials characterized them as a political preemptive strike to fend off growing sentiment elsewhere in Washington to tackle the federal government's soaring deficits by making deep cuts in military spending. The Obama administration has exempted national security from its budget reductions, but Gates said he fears that Congress might not be able to resist for long.

"It is important that we not repeat the mistakes of the past, where tough economic times or the winding down of a military campaign leads to steep and unwise reductions in defense," Gates said. He cited threats from Iran, North Korea and other countries -- in an implicit reference to China -- as justification for continued overall growth in the Pentagon's budget.

(Iraq commander told to eliminate his own job)

After a decade in which its budget has nearly doubled, the Defense Department confronts its most significant fiscal constraints since the end of the Cold War. These constraints are pressing the military to accept major changes in the way it operates, especially as it tries to end long-running wars in Iraq and Afghanistan.

The initiatives Gates detailed are part of his previously announced effort to save $100 billion over five years by trimming overhead and shrinking bureaucracy so that more money can be spent on troops and weapons.

(Opinion: A defense plan for the 21st century)

That bureaucracy includes the U.S. Joint Forces Command, which was established in 1999 to coordinate training and military doctrine among the branches of the armed services. The command is also involved in organizing the deployment of armed forces around the world.

On Monday, the defense secretary emphasized that he is not seeking to cut the Pentagon's overall budget. Rather, he said, officials need to demonstrate a newfound thriftiness to keep deficit hawks elsewhere in the government at bay. "The culture of endless money that has taken hold must be replaced by a culture of savings and restraint," he said.