Defense secretary says Pentagon may have to stop using three aircraft carriers if massive sequestration cuts are not avoided

The US defense secretary, Chuck Hagel, warned on Wednesday that the Pentagon may have to stop using 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.

Hagel told reporters that 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. He laid out a worst-case scenario for the US military if the Pentagon is forced to cut more than $50bn from the 2014 budget and $500bn over the next 10 years, as a result of Congressionally mandated spending cuts. Congress continues to debate spending bills.

Going from 11 to eight or nine carrier strike groups would bring the navy to its lowest number since the second world war, Hagel said. The troop cuts would bring the army back to levels not seen since at least 1950, eroding the military's ability to keep forces deployed and ready for combat overseas.

Hagel said the US 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 US 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.

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

The budget cuts come from a law enacted two years ago that ordered the government to come up with $1.2tn 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, the Pentagon faces a cut of $54bn from current spending if Congress fails to reverse the automatic cuts, according to calculations by congressional budget aides. The base budget must be trimmed to $498bn, with cuts of about 4% hitting already reduced spending on defense, nuclear weapons and military construction.