The United States now faces new array of security challenges from across the globe, including the rise of new powers in Asia; behaviour of countries like Iran and North Korea and proliferation of lethal weapons, Defence Secretary Leon Panetta said on Thursday.
"Even as our large-scale military campaigns recede, the United States still faces complex and growing array of security challenges across the globe," Panetta said at a Pentagon news conference on the occasion of release of new strategic review document of the Department of Defense.
"Unlike past drawdowns, when oftentimes the threats that the country was facing went away, the fact is that there remain a number of challenges that we have to confront, challenges that call for reshaping of America's defence priorities, focusing on the continuing threat of violent extremism, which is still there and still to be dealt with, proliferation of lethal weapons and materials, the destabilising behaviour of nations like Iran and North Korea, the rise of new powers across Asia, and the dramatic changes that we've seen unfold in the Middle East," Panetta said.
Panetta, however, did not identify the countries which poses threat to the US.
But moments earlier, President Barack Obama said that China poses a long term security threat to the United States.
"All of this comes at a time when America confronts a very serious deficit and debt problem here at home, a problem which is itself a national security risk that is squeezing both the defence and domestic budgets," he said.
"The department would need to make a strategic shift regardless of the nation's fiscal situation. We are at that point in history. That's the reality of the world we live in. Fiscal crisis has forced us to face this strategic shift -- shift that's taking place now," he said.
Panetta said four over-arching principles have guided US deliberations on this strategic review.
"One, we must maintain the world's finest military; one that supports and sustains the unique global leadership role of the United States in today's world. Two, we must avoid hollowing out the force. A smaller, ready and well-equipped military is much more preferable to a larger, ill- prepared force that has been arbitrarily cut across the board," he said.
"Third, savings must be achieved in a balanced manner, with everything on the table, including politically sensitive areas that will likely provoke opposition from parts of the Congress, from industry and from advocacy groups. That's the nature of making hard choices," he said.
"Four, we must preserve the quality of the all-volunteer force and not break faith with our men and women in uniform or their families," he added.
Panetta said the US military will remain capable across the spectrum.
"We will continue to conduct a complex set of missions, ranging from counter-terrorism, ranging from countering weapons of mass destruction, to maintaining a safe, secure and effective nuclear deterrent. We'll be fully prepared to protect our interests, defend our homeland and support civil authorities," he said.
"The US joint force will be smaller and it will be leaner. But its great strength will be that it will be more agile, more flexible, ready to deploy quickly, innovative and technologically advanced. That is the force of the future," he said.
"As we move towards this new joint force we are also rebalancing our global posture and presence, emphasising the Pacific and the Middle East. These are the areas where we see the greatest challenges for the future," he said.
The US military will increase its institutional weight and focus on enhanced presence, power projection and deterrence in Asia- Pacific.
This region is growing in importance to the future of the United States in terms of its economy and our national security. This means, for instance, improving capabilities that maintain its military's technological edge and freedom of action.
At the same time, he said, the US will place a premium in maintaining our military presence and capabilities in the broader Middle East.
"The United States will continue to strengthen its key alliances, to build partnerships and to develop innovative ways to sustain US presence elsewhere in the world," he said.
Panetta said the strategy review concluded that the United States must have the capability to fight several conflicts at the same time.
"How we defeat the enemy may very well vary across conflicts. But make no mistake: We will have the capability to confront and defeat more than one adversary at a time. As a global force, our military will never be doing only one thing. It will be responsible for a range of missions and activities across the globe of varying scope, duration and strategic priority," he said.
As the US reduces the overall defence budget, the US will protect, and in some cases increase, its investments in special operations forces; in new technologies, like ISR and unmanned systems; in space, and in particular in cyberspace capabilities; and also its capacity to quickly mobilise if necessary.
"These investments will help the military retain and continue to refine and institutionalize the expertise and capabilities that have been gained at such great cost over the last decade," Panetta said.