US Defense Secretary Chuck Hagel has commended the US Army for its contributions to national defense over the last 13 years of conflict and noted that demand for what the Army does for the nation will not diminish during the period of uncertainty and change that lies ahead.

Speaking at the Association of the United States Army's annual conference, Hagel said this is a time of great transition for the Army as the US military responsibly ends its combat role in Afghanistan and transitions to a train-advise-and-assist mission.

"As the Army emerges from over 13 years of large-scale combat operations -- the longest in its history -- it faces new challenges," Hagel said. "The world's becoming more volatile, less predictable, and, in many ways, more threatening at the same time our defense budgets are declining."

He noted that more than 1 million US soldiers have deployed to the wars in Iraq and Afghanistan over the last 13 years.

"Seventy percent of US personnel wounded in action over the last 13 years were from the Army," he continued, "and countless soldiers have come home with visible -- and invisible -- wounds of war."

"Through the crucible of combat, and a grinding counterinsurgency campaign, the American soldier fought on," he said. "As a result, today's Army is as battle-tested as it has ever been."

The Defense Secretary stressed that the strength, resilience, and dedication of the US Army is what makes it the foundation of America's national security and its contribution to US security is as critical today as ever.

"We see it in West Africa where soldiers will soon deploy as a key part of America's contribution to the global effort to stop the spread of Ebola before it becomes an even more of a grave threat," he said.

Hagel noted that while a another Iraq or Afghanistan-type campaign is unlikely, this does not mean that demand for the Army is diminishing, or that the Army's place in US national security strategy is eroding.

Stressing that there will always be a need for a modern, ready, well equipped, well-trained standing Army, Hagel noted that this is especially true in a global security environment that is more unpredictable than ever and that will require America to lead the world in response.