Eight years after the Sept. 11 attacks, U.S. President Barack Obama says the U.S. "will never falter" in its pursuit of al Qaeda and its allies.
The U.S. came together as one after the terror attacks, Obama said, "united not only in our grief but in our resolve to stand up for the country we love."
"Let us renew the true spirit of that day -- not the human capacity for evil but the human capacity for good," Obama said. "Not the desire to destroy but the impulse to save and to serve and to build."
He made the remarks from rainy Washington, at the 9/11 memorial at the Pentagon where he laid a wreath. He'll later meet with the families of the 184 people who died when a jet slammed into the headquarters of the U.S. Department of Defense.
Obama decided to stay closer to home for this anniversary, perhaps seeking to distinguish himself from his predecessor, George W. Bush, who consistently attended World Trade Center anniversaries to galvanize support for the wars in Iraq and Afghanistan.
Obama's decision not to fly to New York comes as public sentiment in the U.S. toward their country's involvement in Afghanistan is souring, as combat deaths grow and questions persist about flawed Afghan elections.
And while U.S. troops are slowly being drawn down from Iraq, it's happening at a much slower pace than Obama envisioned while he campaigned for the presidency. Defense Secretary Robert Gates has spoken of "a certain war-weariness on the part of the American people."
U.S. Vice President Joseph Biden and his wife Jill attended the New York ceremony, along with Homeland Security Secretary Janet Napolitano.
There, the families of the World Trade Center attack victims gathered to read each of the names of the 2,752 killed that sunny Tuesday morning in 2001.
One new name was added to the list of victims read. His name is Leon Heyward and he died last year of lymphoma and lung disease. The medical examiner's office ruled Heyward was a homicide victim because his death was a result of having been caught in the toxic dust cloud just after the Trade Center towers collapsed.
It's the second time the city has added to the victims' list someone who died long after Sept. 11.
Four moments of silence were held, at 8:46 a.m., 9:03 a.m. ET, to mark the times when the first and second hijacked planes hit the Trade Center buildings, and then again at 9:59 a.m. and 10:29 a.m., when the south and north towers fell.
Friday was the first time the anniversary was observed as a national day of service, following an order signed this year by Obama.
Obama urged Americans to mark the anniversary with acts of community service, saying: "We can summon once more that ordinary goodness of America, to serve our communities, to strengthen our country and to better our world."
"From this day forward, we will safeguard the memories of those who died by rekindling the spirit of service that lit our city with hope and helped keep us strong," New York Mayor Michael Bloomberg said at a ceremony in lower Manhattan.
Even eight years after the attacks, work on a 9/11 memorial at the World Trade Center remains stalled, held up by financial and legal wrangling.
Work has begun on the foundation of "Freedom Tower," a planned complex of five new skyscrapers, with a park and memorial in the middle. But progress has been slow, hampered by the financial crisis and the real estate downturn.
Although work on foundations of several key elements is underway and the frame for the future tower is rising, for the most part the site still looks like a big hole, eerily reminiscent of the wasteland created eight years ago today by two jetliners driven by a two groups of terrorists.
