"The US and international community will continue to work with Afghanistan, Pakistan and India to advance security in this critically important part of the world," Defence Secretary Chuck Hagel said.
In his speech at the University of Nebraska-Omaha, Hagel also observed that rise of nations like China, India and Indonesia will help shape the 21st century.
For the first time in 12 years of US and international involvement in Afghanistan, the Afghan forces have formally assumed lead responsibility for security, Hagel noted.
"It keeps us on track to responsibly end the war next year and transition to a far more limited non-combat mission to assist the Afghan government as it takes full responsibility for the country's future," said Hagel.
Hagel said the forces that are reshaping the world include the rising Asian countries, outbreak of revolution and sectarian conflicts across Middle East and North Africa, along with continuing impact of financial crises and recessions in Europe and the rise of China, India and Brazil.
"These shifts are all interconnected," he said. Hagel said US is taking the rebalance in Asia Pacific region because of the its growing importance to America's future security and prosperity.
"America has always been a Pacific power. The rebalance engages America's relationships with countries across the region, including rising powers like China, India and Indonesia," he said.
World nations have an interest in building a world order based on strong economic ties, mutual security interests and respect for rules, norms, and institutions that underpin them, he noted.
"In Asia and beyond, our approach to security in the 21st century is to strengthen alliances, build new partnerships and forge coalitions of common interest that help resolve problems and prevent conflict.
We are doing this in Europe through our renewed commitment to the NATO Alliance and in Middle East, Africa, and Latin America. All of these regions will help define the world's future," the US defence secretary said.
He said the US is employing a lighter-military footprint approach to enhance defence cooperation and the capabilities of allies through military engagements and joint exercises which enables it to respond to the crises more quickly.
Clarifying that US will maintain its capacity to meet its commitments and deter aggression, he said the most sustainable and wisest approach to security in the 21st century will be to help allies in contributing to their own security and common interests.