President Joe Biden marked the 22nd anniversary of the September 11, 2001, terrorist attacks on Monday, telling servicemembers gathered in Anchorage, "terrorism -- including political and ideological violence -- is the opposite of all we stand for as a nation."

"We must not succumb to the poisonous politics of difference and division, must never allow ourselves to be pulled apart attending manufactured grievances, we must continue to stand united," he said. "We all have an obligation, a duty, a responsibility to defend, to preserve, to protect our democracy."

Biden, who has previously marked 9/11 with visits to sites in Shanksville, Pennsylvania, the Pentagon, and Ground Zero in New York acknowledged that though Elmendorf Air Force Base is not "located at Ground Zero, we know the distance did not dull or diminish the pain we felt across the nation of September 11." Biden was speaking at the base as he traveled back from Hanoi, Vietnam, his final stop on a whirlwind trip to Asia to meet with Vietnamese leaders and attend the G-20 summit in New Delhi.

"Because we know that on this day, 22 years ago, [planes] from this base were scrambled on high alert to escort planes through the airspace, Alaskan communities opened their doors to stranded passengers, American flags sold out in every store and were placed in front of seemingly every home," he said. "We know that on this day, every American's heart was wounded, yet in every big city, small town, suburb, rural town, tribal community, American hands went up, ready to help where they could, ready to serve like so many of you here."

In the days that followed 9/11, the president acknowledged, national unity reached a fever pitch in the wake of the terrorist attacks.

"Now it shouldn't take a national tragedy to remind us of the power of national unity, but that's how we truly honor those we lost on 9/11," he said. "By remembering what we can do together. To remember what was destroyed, what can we repair, what was threatened, what we fortified, what was attacked -- an indomitable American spirit prevailed over all of it."

And he touted the steps the nation had taken in the years since 9/11 to eradicate terrorism, noting American forces "served and sacrificed, again and again, to defend our democracy and deny terrorists the safe haven, following Osama bin Laden to the end of earth -- and not only send him to the gates of hell 12 years ago," but took out al Qaeda chief Ayman al-Zawahiri last year.

He also took the opportunity to pay tribute to the late Sen. John McCain, whose memorial he stopped by earlier on Monday in Hanoi.

"One thing I always admired about John was how he put duty to country first, and that's not hyperbole, he did," Biden said. "Above party, above politics, above his own person. This day reminds us, we must never lose that sense of national unity. So, let that be the common cause of our time -- let us honor September 11 by renewing our faith in one another."