Defense Secretary Chuck Hagel warned Wednesday that the Pentagon may have to mothball up to three Navy aircraft carriers and order additional sharp reductions in the size of the Army and Marine Corps if Congress doesn't act to avoid massive budget cuts beginning in 2014.

Speaking to Pentagon reporters, and indirectly to Congress, Hagel said that the full result of the sweeping budget cuts over the next 10 years could leave the nation with an ill-prepared, under-equipped military doomed to face more technologically advanced enemies.

In his starkest terms to date, Hagel laid out a worst-case scenario for the U.S. military if the Pentagon is forced to slash more than $50 billion from the 2014 budget and $500 billion over the next 10 years as a result of Congressionally-mandated automatic spending cuts.

The Pentagon has been ratcheting up a persistent drumbeat about the dire effects of the budget cuts on national defense, and as Congress continues to wrangle over spending bills on Capitol Hill.

Going from 11 to eight or nine carrier strike groups would bring the Navy to its lowest number since World War II. And the troop cuts would shear the Army back to levels not seen since at least 1950, eroding the military's ability to keep forces deployed and combat ready overseas.

Detailing options, Hagel said America may have to choose between having a highly capable but significantly smaller military and having a larger force while reducing special operations forces, limiting research and cutting or curtailing plans to upgrade weapons systems.

That second option, he said, would likely result in the U.S. military using older, less effective equipment against more technologically advanced adversaries. And it would have a greater impact on private defense companies around the country.

The U.S., said Hagel, risks fielding a military force that in the next few years would be unprepared due to a lack of training, maintenance and upgraded equipment.

And, even if the Pentagon chooses the most dramatic cuts, Hagel said it would still "fall well short" of meeting the reductions required by the automatic budget cuts, particularly during the first five years.

While noting that no final decisions have been made, Hagel laid out a few specific ideas under consideration.

He said that to achieve the savings by shrinking the force, the Pentagon might have to cut more than 100,000 additional soldiers from the Army -- which is already planning to go from a wartime high of about 570,000 to 490,000 by 2017. And the current plan to reduce the size of the Marine Corp to 182,000 from a high of about 205,000 could also be changed -- cutting it to as few as 150,000 Marines.

He added that the Air Force could lose as many as five combat air squadrons as well as a number of other bomber and cargo aircraft.

"This strategic choice would result in a force that would be technologically dominant, but would be much smaller and able to go fewer places and do fewer things, especially if crises occurred at the same time in different regions of the world," said Hagel.

Another option, he said, would be to make fewer cuts in the size of the force, and instead cancel or curtail many modernization programs.

In addition he said that the Pentagon is taking a close look at cuts to health care benefits, military housing allowances, cost-of-living adjustments and civilian pay raises.

Hagel repeated his plans -- announced two weeks ago -- to cut top Pentagon and military staff and spending by 20 percent. The savings, which will apply to his office, that of the Joint Chief's chairman and also the Pentagon headquarters offices of the Army, Navy, Air Force and Marine Corps., could total between $1.5 billion and $2 billion over the next five years and will target personnel, including civilians and contractors.

The details Hagel described Wednesday are the result of a lengthy review by top Pentagon and military leaders that looked at the impact of budget cuts on the department and developed a series of options to deal with them.

The budget cuts stem from a law enacted two years ago that ordered the government to come up with $1.2 trillion in savings over a decade. The law included the threat of annual automatic cuts as a way of forcing lawmakers to reach a deal, but they have been unable to do so.

As a result, come January, the Pentagon faces a cut of $54 billion from current spending if Congress fails to reverse the automatic cuts, according to calculations by Capitol Hill budget aides. The base budget must be trimmed to $498 billion, with cuts of about 4 percent hitting already reduced spending on defense, nuclear weapons and military construction.

Congress has shown little inclination to undo the so-called sequester cuts, though talks between the White House and a handful of Senate Republicans have intensified in recent weeks.

Some lawmakers and staff aides say the new, deeper reductions in the Pentagon's budget to could be the jolt that prompts lawmakers to step back from the automatic cuts.