Defense Secretary Leon Panetta cautioned global rivals on Sunday not to misjudge U.S. plans to slash military spending over the next decade, saying America would still field the world's strongest military and nobody should "mess with that.", Reuters reported. Panetta reminded Republican presidential contenders who have criticized the Pentagon's new military strategy that the decision to cut $487 billion in defense spending was made by a bipartisan Congress. Some Republicans have expressed concerns about the cuts and their impact. Leading Republican presidential candidate Mitt Romney charged that President Barack Obama's new military strategy unveiled this week was "inexcusable and unthinkable" because it would reduce U.S. global military capability. The new strategy, which is meant to guide defense spending over the next decade as the military cuts back, calls for greater emphasis on Asia even as the Army and Marines shrink to become smaller and more agile forces. "I think this country has to deal with the reality of the situation that we're confronting," Panetta said in a pre-recorded interview. "We're coming out of a decade of war. We're facing a huge budget crisis in this country. The Congress said ... we have to reduce the defense budget by $487 billion." General Martin Dempsey, the top U.S. military officer as chairman of the Joint Chiefs of Staff, told "Face the Nation" he worried that some countries might misunderstand the debate Americans are having over changing strategy and the need to cut defense spending. "There may be some around the world who see us as a nation in decline, and worse, as a military in decline. And nothing could be further from the truth," Dempsey said. Panetta said U.S. rivals should not misunderstand the situation. "I think the message that the world needs to understand is: America is the strongest military power and we intend to remain the strongest military power and nobody ought to mess with that," he said. Obama and Congress agreed in August to cut some $487 billion in defense spending over the next decade as part of efforts to bring of the nation's $14 trillion debt under control. Defense spending could be cut by another $600 billion as part of the August spending deal unless Congress compromises on an alternative. Congress missed the deadline for reaching an agreement but could still take action to override the cuts before they are due to go into force next year. Obama, in unveiling the new defense strategy at a Pentagon news conference on Thursday, noted that even with the $487 trillion in cuts to projected spending, the defense budget would continue to grow in nominal terms. He also said the U.S. defense budget would still be by far the world's largest - roughly the size of the 10 next-biggest defense budgets combined. If the second round of defense cuts takes place, the Pentagon's base budget would fall to roughly $472 billion in fiscal 2013 - about the level of fiscal 2007 in inflation-adjusted dollars, according to an analysis by Todd Harrison of the Center for Strategic and Budgetary Assessments. That represents a real cut of about 11 percent. It would remain at roughly the same level for about eight years, growing only at about the pace of inflation, Harrison's analysis said. Panetta told National Public Radio on Sunday the Pentagon was not ready for cuts of that magnitude. "If we had to do over a trillion dollars in cuts in this department, I have to tell you that the strategy that we developed, we'd probably have to throw that out the window and start over," he said. Obama campaign adviser David Axelrod downplayed the likelihood that the second round of cuts would actually occur, telling ABC's "This Week" program "we expect we're going to deal with that ... during the course of this year."