American military readiness starts deteriorating at midnight. Flights will be grounded. Ships will stay dockside. Army unit training will stop.

That’s the assessment of the top Pentagon officials in the wake of abrupt and deep budget cuts that will take effect today.

Newly installed Secretary of Defense Chuck Hagel, at his first full news conference, said he had high hopes that President Barack Obama and members of Congress would find a solution to their dispute over the federal budget before the reductions go too deep.

“This is the security of the United States of America we’re talking about,” Hagel said.

The budget cuts, known in Washington parlance as sequestration, mean an automatic reduction of $85 billion in programs across the board, including 10 percent — $48 billion — of the Defense Department’s budget, which will be applied during the last half of the budget year.

Hagel and Deputy Secretary of Defense Ashton Carter said the cuts might damage the department.

The trims apply only to budget areas that haven’t been protected, so they won’t affect the costs of military personnel or funding for the war in Afghanistan. But Carter noted that they’ll fall even harder on the unprotected parts of the budget, and three areas in particular will take the biggest blows.

In the civilian workforce, part-time employees may face layoffs and full-time employees face an unpaid day off beginning at some point in April. Among contractors, new orders will be cut or delayed, meaning that fewer workers might be needed.

Military readiness is the third area, Hagel and Carter said, and they stressed that deterioration would speed up and become more of a concern with each passing week. While combat aircraft in Afghanistan and nuclear-capable planes will continue to fly, the Air Force will ground most U.S.-based training flights, according to military officials. This might lead to longer-term problems, as grounded pilots may lose the ratings and delay their return to the air.

The Navy will keep ships in dock, and scheduled maintenance will slow.

As for the Marines, Pentagon officials said they “face significant cutbacks in training,” as does the Army.