U.S. Defense Secretary Leon Panetta on Wednesday urged the Congress to stop an automatic 500- billion-dollar cut to defense spending due to go into effect next year.

"It would be devastating," Panetta said of the additional defense cuts mandated by last summer's debt-ceiling deal when he testified on the proposed fiscal 2013 defense budget before the House Armed Services Committee. "When you take a half a trillion dollars out of the defense budget, it comes with risks."

The defense budget proposal for the next fiscal year -- 525.4 billion dollars for base budget plus 88.5 billion dollars for overseas contingency operations -- includes reductions toward 487 billion dollars in defense spending cuts over 10 years mandated by the Budget Control Act, which the Congress passed last year.

It does not, however, account for more than 500 billion dollars in additional cuts that will go into effect in January if the Congress doesn't act to stop it. Those additional cuts, known as " sequestration," were written into the Budget Control Act as automatic, across-the-board cuts to the federal budget if members of a congressional "super committee" could not agree on spending cuts by a November deadline. And they didn't.

The Congress must do everything possible to avoid sequestration, Panetta said, because it would amount to "a meat-ax approach" of cutting at least 8 percent more from each defense budget category.

"Whatever we can do on both sides to develop an approach that we detrigger sequestration, we're certainly willing to work on that," he said.