NEW YORK, N.Y. - The names of the Sept. 11 dead, some called out by children barely old enough to remember their fallen mothers and fathers, echoed across ground zero Sunday in a haunting but hopeful tribute on the 10th anniversary of the terror attack. "God is our refuge and strength," President Barack Obama said, quoting the Bible.
Weeping relatives of the victims streamed into a newly opened memorial and placed pictures and flowers beside names etched in bronze. Obama and his predecessor, George W. Bush, bowed their heads and touched the inscriptions.
Obama, standing behind bulletproof glass and before the white oak trees of the memorial, read the Bible passage after a moment of silence at 8:46 a.m. (1246 GMT), when the first jetliner slammed into the north tower 10 years ago.
The president, quoting Psalm 46, invoked the presence of God as an inspiration to endure. "Therefore, we will not fear, even though the earth be removed, and though the mountains be carried into the midst of the sea."
The New York ceremony, which ended with the playing of taps in the early afternoon, was the centerpiece of a day of remembrance across the country. It was a chance to reflect on a decade that changed American life, including two wars and the overhaul of everyday security at airports and in big cities.
In a tribute at the Pentagon, Vice-President Joe Biden invoked a "9-11 generation of warriors."
"Never before in our history has America asked so much over such a sustained period of an all-volunteer force," he said. "So I can say without fear of contradiction or being accused of exaggeration, the 9-11 generation ranks among the greatest our nation has ever produced, and it was born — it was born — it was born right here on 9-11."
Defence Secretary Leon Panetta observed a moment of silence at 9:37 a.m. (1337 GMT), marking the time a jet struck the centre of the nation's military. He paid tribute to 6,200 members of the U.S. military who have died in the Iraq and Afghan wars.
In Shanksville, Pennsylvania, a choir sang at the Flight 93 National Memorial, and a crowd of 5,000 listened to a reading of the names of 40 passengers and crew killed aboard the plane a decade ago.
In New York, family members were reading the names of 2,983 victims — 2,977 killed in New York, Washington and Pennsylvania on Sept. 11, 2001, and six killed in the first terror attack on the trade centre, a truck bomb in 1993.
"You will always be my hero," Patricia Smith, 12, said of her mother.
Nicholas Gorki remembered his father, "who I never met because I was in my mother's belly. I love you, Father. You gave me the gift of life, and I wish you could be here to enjoy it with me."
Peter Negron, 21, whose father worked on the 88th floor of the north tower, said that in the decade since the attack, he had tried to teach his younger brother lessons he had learned from their father.
"I decided to become a forensic scientist," Negron said. "I hope that I can make my father proud of the young men my brother and I have become. I miss you so much, Dad."
Bush quoted a letter from President Abraham Lincoln to a mother who lost all five of her sons in the Civil War.
"I pray that our heavenly father may assuage the anguish of your bereavement," Bush said.
Obama and Bush were joined by their wives as they walked up to one of the two reflecting pools built over the towers' footprints, part of a Sept. 11 memorial that was opened for relatives of the victims.
Sumika Tanaka came with her mother from Tokyo to find the name of her husband, who was working for a Japanese bank in the south tower when he was killed.
"It's not going to disappear," said Tanaka, 30. "It will be here 10 years from now. And that's what is important to me."
Some family members held children on their backs who were not yet born when the towers were attacked.
New York Mayor Michael Bloomberg, opening the ceremony of remembrance, said: "Although we can never un-see what happened here, we can also see that children who lost their parents have grown into young adults. ... Good works have taken root in public service."
As the sun rose, an American flag fluttered over six stories of the rising 1 World Trade Center. The sky was clear blue with scattered white clouds and a light breeze, not unlike the Tuesday morning 10 years ago.
The site looked utterly different than it had for any other Sept. 11 anniversary: Along with the names in bronze, there were two manmade waterfalls directly on the footprints of the towers, surrounded by dozens of white oak trees.
The anniversary arrived with security officials in New York and Washington on alert. Ahead of the anniversary, the federal government had warned local authorities of a tip about a possible car-bomb plot linked to al-Qaida.
Remembrances around the nation and world marked a decade of longing for loved ones lost in the attack.
The anniversary revived memories of a September morning when terrorists crashed hijacked planes into the World Trade Center and the Pentagon, and a fourth plane crashed into a field in rural western Pennsylvania. Of heroism and Samaritans and unthinkable fear. And of nearly 3,000 killed at the hands of a global terror network led by Osama bin Laden, himself now dead.
People across America planned to gather to pray at cathedrals in their greatest cities and to lay roses before fire stations in their smallest towns. Around the world, many others planned to do something similar.
Obama and his wife flew from New York to lay a wreath at the Flight 93 National Memorial near the town of Shanksville, Pennsylvania, where a day earlier Bush and former President Bill Clinton and Biden joined the families of the 40 passengers and crew aboard the jet who fought back against their hijackers.
From Shanksville, the Obamas returned to Washington, where they crossed the Potomac River to the Pentagon to lay a wreath at the memorial there.
"The moment America's democracy was under attack our citizens defied their captors by holding a vote," Bush said. Their choice cost them their lives.
The passengers and crew gave "the entire country an incalculable gift: They saved the Capitol from attack," an untold amount of lives and denied al-Qaida the symbolic victory of "smashing the centre of American government," Clinton said.
They were "ordinary people given no time at all to decide and they did the right thing," he said.
"And 2,500 years from now, I hope and pray to God that people will still remember this."
As the anniversary arrived around the world, people paid tribute in formal ceremonies and quiet moments.
In Japan, they gathered Sunday to lay flowers before a glass case containing a small section of trade centre steel, and remembered 23 employees of Fuji Bank who never made it out of the towers.
A village in the Philippines offered roses, balloons and prayers for an American victim whose widower built 50 brightly colored homes there, fulfilling his late wife's wish to help the Filipino poor.
In Malaysia, Pathmawathy Navaratnam woke up and, as she has done every morning for 10 years, wished "good morning" to her son, a 23-year-old financial analyst who was killed in New York.
"He is my sunshine. He has lived life to the fullest, but I can't accept that he is not here anymore," said Navaratnam. "I am still living, but I am dead inside."
In a reminder of the war that started in the wake of the attacks, 77 American soldiers were wounded when a Taliban suicide bomber detonated a truck bomb outside the gates of a U.S. base in eastern Afghanistan. Two Afghans were also killed.
Obama also planned to visit the Pentagon and was to speak at a Sunday evening service at the Kennedy Center.
The hundreds of ceremonies across the country and around the globe included memorial Mass at St. Patrick's Cathedral in New York and a ceremony featuring nine-stories-tall replicas of the twin towers on a plaza in Paris.
Associated Press writer Joe Mandak in Shanksville, Pennsylvania, contributed to this report.
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