US president Barack Obama said today that the September 11th victims would be remembered "no matter how many years pass" as Americans marked the 11th anniversary of the attacks in which nearly 3,000 people were killed by airliners hijacked by Islamist militants.
Two of the passenger jets brought down the twin tof New York City's World Trade Centre, another hit the Pentagon outside Washington and a fourth crashed in a field in Pennsylvania when passengers aboard that flight fought back against the hijackers.
Mr Obama, speaking at the Pentagon where 184 people were killed, told victims' families that the whole country shares their loss.
"Eleven times we have paused in remembrance and reflection, in unity and in purpose," Mr Obama said. "This is never an easy day, but it is especially difficult for all of you, the families of nearly 3,000 innocents who lost their lives.
"But no matter how many years pass, no matter how many times we come together on this hallowed ground, know this: That you will never be alone, your loved ones will never be forgotten. They will endure in the hearts of our nation because through their sacrifice they helped us make the America we are today, an America that has emerged even stronger."
Speaking under clear blue skies that recalled the crisp morning of September 11th, 2001, Mr Obama said America's fight is not with Islam but with al-Qaeda, the group responsible for the attacks, and its allies.
This is a line he has used several times since taking office promising to mend ties with the Muslim world.
"I've always said our fight is with al-Qaeda and its affiliates, not with Islam or any other religion," he said. "This country was built as a beacon of freedom and tolerance."
At Ground Zero in New York where the towers once stood, the annual reading of the list of 2,983 people killed at the three sites began at 8.39am (1.39pm Irish time).
The first names were read by Patricia Abbott, wife of Alan Jay Richman, who died at the trade centre, and by Allison Adams, wife of Patrick Adams, who also died in the trade centre's collapse. It will take 198 people more than three hours to read the list alphabetically.
The list excludes the 19 hijackers, who died carrying out the attacks.
Moments of silence were observed at 8.46am, 9.03am, 9.37am and 10.03am, the times of impact for the four planes, and again at 9.59am and 10.28am, the times that the north tower and then the south tower fell.
As the time of the reading approached, family members, uniformed police and firefighters milled about the vast, twin reflecting pools that mark the footprints of the towers, their edges etched with the names of the victims. Many brought pictures of their loved ones.
Alyson Low (41) of Fayetteville, Arkansas, carried a picture of her sister, Sara Elizabeth Low, who was a flight attendant on American Airlines Flight 11, the first plane to crash, striking the north tower. "I'm tired," Ms Low said, tearfully. "I am just so tired."
Twelve-year-old Hailey Perez, of Clifton, New Jersey, was in attendance for the second time, having come to memorial ceremonies for the first time a year ago. She carried a white-framed photo of her godfather, Kenny Lira, who worked on the 110th floor of the south tower.
For years she had not come to the annual ceremony, but now that the memorial plaza is complete and the Freedom Tower nears completion to replace the fallen buildings, she feels more comfortable attending, she said. "It's better than previous years because I didn't want to come here and look at all the rubble," she said.
In previous years, politicians including US presidents, governors and New York City mayors have participated in the reading of the names, or have read from the Bible or recited passages from literature. This year only the families of the more than 2,750 who were killed at the World Trade Centre will appear on the podium to read their names.
Politicians were in attendance. But under rules set down in July by the National September 11th Memorial and Museum, chaired by New York mayor Michael Bloomberg, none may speak or participate in the reading of names. Mr Bloomberg was on hand, as was New York governor Andrew Cuomo and former New York mayor Rudolf Giuliani, who was mayor when the attacks occurred.
In Washington, Mr Obama and first lady Michelle Obama observed a moment of silence for the September 11th victims on the south lawn of the White House before heading across the Potomac River to the Pentagon.
After the Pentagon ceremony, Mr Obama stopped at Arlington National Cemetery, where he and the first lady paid their respects at the graves of military service members killed in Iraq and Afghanistan.
Vice president Joe Biden was in Shanksville, Pennsylvania, where 40 passengers aboard United Flight 93 were killed when that plane crashed as they fought back against their hijackers. US authorities say the hijackers planned to crash that plane into the US Capitol in Washington.
Reuters