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 does not act to avoid massive budget cuts beginning in 2014.

Speaking to Pentagon reporters, and indirectly to Congress, Hagel said 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 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 that took effect this year.

The Pentagon has been ratcheting up a persistent drumbeat about the dire effects of the budget cuts on national defense as Congress continues to wrangle over spending bills. Hagel insisted the department is not exaggerating the impact, as it was accused of doing last winter as it tried to stave off the first round of the so-called “sequester” cuts.

“I know there’s politics in all this,” Hagel said. “But what we’re trying to project here is not crying wolf or not trying to overstate or overhype.”

Sitting alongside Hagel, Navy Adm. James Winnefeld, vice chairman of the Joint Chiefs, said a major frustration is that the Pentagon doesn ot know what budget totals Congress will eventually decide on, or when lawmakers will make a decision.

“What we were doing here is teeing up choices. We haven’t made those choices yet,” said Winnefeld. “When we finally get an answer on what the financial outlook is going to look like, we will then begin to make those choices.”

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 could shear the Army back to levels not seen since 1940, before its wartime buildup.

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

The second option, he said, would likely result in the using older, less effective equipment against more technologically advanced adversaries. It would also have a greater impact on private defense contractors around the country.

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

While noting that no final decisions have been made, Hagel laid out a few specific ideas under consideration. He said that to achieve the required 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, after U.S. forces leave Afghanistan. And the current plan to reduce the size of the Marine Corps to 182,000 from a high of about 205,000 could also be changed — cutting it to as few as 150,000.

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

The 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 after lawmakers failed to devise their own cuts.

As a result, come January, the Pentagon faces a cut of $54 billion from current spending, 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.