Both U.S. Vice President Joe Biden and Defense Secretary Leon Panetta on Sunday vowed to pursue relentlessly al-Qaeda until it is dismantled, as they joined others in observing the 10th anniversary of the Sept. 11, 2001 attacks on the country at the Pentagon.

In this photo released by the US Department of Defense (DOD), (L to R) Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, Defense Secretary Leon E. Panetta and Vice President Joe Biden watch the laying of memorial wreaths at the Pentagon 9/11 observance ceremony, honoring the 184 victims killed when American Airlines Flight 77 crashed into the Pentagon during a terrorist attack 10 years ago, at the Pentagon outside Washington DC, capital of the United States, Sept. 11, 2011. (Xinhua/DOD photo/Chad J. McNeeley)
A moment of silence at 9:37 am EDT marked the exact time the Pentagon was hit by a hijacked American Airlines jetliner a decade ago, an attack that left 184 people perished.

At the Pentagon Memorial dedicated to the dead, 184 soldiers each laid a single wreath of white flowers on 184 wing-shaped benches one by one, on which names of the dead were inscribed.

"You will not stop until al-Qaeda is not only disrupted, but completely dismantled and ultimately destroyed," Biden said of the U.S. military fighting two wars in Afghanistan and Iraq, launched respectively in October 2001 and March 2003 in direct response to the 9/11 attacks.

In this photo released by the US Department of Defense (DOD), a U.S. Marine lays a wreath at the Pentagon 9/11 observance ceremony, honoring the 184 victims killed when American Airlines Flight 77 crashed into the Pentagon during a terrorist attack 10 years ago, at the Pentagon outside Washington DC, capital of the United States, Sept. 11, 2011. (Xinhua/DOD photo/Chad J. McNeeley)
He noted the "incredible price" the military has paid for the wars, including 4,478 troops fallen in Iraq, 1,648 in Afghanistan, and more than 40,000 wounded in both countries, some of whom will require "care and support the rest of their lives."

"To this day, and by these memorials to each victim, we pledge to never forget the enemy that made this happen, why we fight them, and why we will never stop fighting them to make sure that what happened here and in New York City and in the field in Pennsylvania never happens again," Defense Secretary Leon Panetta said.

The White House said President Barack Obama, who appeared at ceremonies in Lower Manhattan, New York City and Shanksville, Pennsylvania, plans to lay a wreath at the Pentagon Memorial later Sunday.  

VietNamNet/Xinhuanet