US Defense Secretary Leon Panetta on Monday called on Congress to reach a deficit-cutting deal after a "supercommittee" failed to do so, warning that automatic spending cuts would gut the military.

Panetta, saying he had "never been so concerned" about the ability of lawmakers to solve the nation's problems in his four decades of public service, warned that slashing defense spending would result in a "hollow force."

The bipartisan committee said Monday it had failed to find a way to cut US deficits by $1.2 trillion over 10 years, meaning that tough automatic cuts to domestic and military spending will occur in January 2013 without a new deal.

"The failure of the Congressional Supercommittee to reach an agreement on deficit reduction is a setback for the country's efforts to achieve fiscal responsibility while protecting our national security," Panetta said.

"If Congress fails to act over the next year, the Department of Defense will face devastating, automatic, across-the-board cuts that will tear a seam in the nation's defense."

"In my four decades involved with public service, I have never been more concerned about the ability of Congress to forge common-sense solutions to the nation's pressing problems," Panetta said in a statement.

For weeks, Panetta has offered stark warnings that the automatic cuts to the Pentagon's budget would leave the military slower, weaker and smaller than at any time since World War II.

"The half-trillion in additional cuts demanded by sequester would lead to a hollow force incapable of sustaining the missions it is assigned," he said.

"If implemented, sequester would also jeopardize our ability to provide our troops and their families with the benefits and the support they have been promised. Our troops deserve better, and our nation demands better."

He urged lawmakers not to repeal the sequester requirement for automatic spending cuts, but indeed to strike a new deal for $1.2 trillion in deficit reduction.