President Barack Obama Tuesday hailed the "9/11 generation" of US veterans and 6,200 service members who perished in the "hard decade of war" spawned by the September 11 attacks.

Obama, speaking to the 93rd annual convention of the American Legion, paid tribute to millions of servicemen and women who had signed up after the world's deadliest terror strike 10 years ago killed nearly 3,000 people.

"Today, as we near this solemn anniversary, it's fitting that we salute the extraordinary decade of service rendered by the 9/11 generation -- the more than five million Americans who have worn the uniform over the past 10 years," Obama said.

"Today we pay humble tribute to the more than 6,200 Americans in uniform who have given their lives in this hard decade of war. We honor them all."

Obama said the 9/11 veterans had become a "one America" team that changed the way their country fights and wins its wars and had learned the cultures of the lands in which they had served.

"Trained to fight, they've taken on the role of diplomats, mayors and development experts, negotiating with tribal sheikhs, working with village shuras, and partnering with communities," Obama said.

"We see the scope of their sacrifice in the tens of thousands who now carry the scars of war, both seen and unseen -- our remarkable wounded warriors.

"Most profoundly, we see the wages of war in those patriots who never came home. They gave their all, their last full measure of devotion, in Kandahar and the Korengal and Helmand, in the battles for Baghdad and Fallujah and Ramadi."

Obama appeared to be seeking to unite his nation to honor war veterans ahead of the September 11 anniversary, despite the fierce political divisions sparked by the anti-terror campaign.

He praised US forces for toppling the Taliban in weeks, driving Al-Qaeda from the terror camps where they plotted the September 11 attacks.

"When the decision was made to go into Iraq, our troops raced across deserts and removed a dictator in less than a month," Obama said, referring to a conflict which he vigorously opposed.

"When insurgents, militias and terrorists plunged Iraq into chaos, our troops adapted, endured ferocious urban combat, reduced the violence and gave Iraqis a chance to forge their own future," he said.

The president also noted the surge strategy he ordered to revive the war effort in Afghanistan and the killing of Al-Qaeda's leader in one of the high points of his presidency.

"A few months ago, our troops achieved our greatest victory yet in the fight against those who attacked us on 9/11 -- delivering justice to Osama bin Laden in one of the greatest intelligence and military operations in American history."

"Credit for these successes, this progress, belongs to all who have worn the uniform in these wars."