Washington: US President Barack Obama on Friday led a moment of silence at the start of eighth anniversary commemorations of the September 11 attacks in 2001 when 3,000 people died in the world`s deadliest terror strike.
At exactly 8:46 am (1246 GMT) when the first plane piloted by al Qaeda hijackers slammed into the North tower of New York`s World Trade Centre, Obama and First Lady Michelle Obama stood with heads bowed outside the White House.
On a rain-swept day so different than that crisp September morning eight years ago, ceremonies were also being held in New York, at the Pentagon and in a Pennsylvania field where a fourth plane crashed short of its target.
It was the first time that Obama, who was driving to work as a state senator in Illinois when he learned of the attacks on the radio, had led the national remembrance ceremonies as president.
At New York`s Ground Zero, all that is left of the two huge towers that were toppled in wave of fire and debris by fuel-laden planes, volunteers read the names of the 2,752 people killed in the strike at the heart of US might.
Obama stepped out in front of the South Portico of the White House, with First Lady Michelle Obama, who was wearing a black dress.
After three chimes played by a US Marine in ceremonial dress, the first couple bowed their heads and observed the moment of silence, joined by around 150 members of the White House staff.
Obama raised his head, and put his hand over his heart as a Marine bugler played a haunting rendition of Taps, the military lament played over soldiers` graves.
Above, the huge American flag on top of the White House hung limply at half-mast.
For hours before the ceremony, rain had sluiced Washington, but moments before Obama and the First Lady appeared the rain tapered off and they were able to stand bare-headed.
As soon as they returned to the White House, the deluge resumed.
The President later headed to the Pentagon to lay a wreath and make remarks at the spot where another hijacked airliner crashed, on a day which sent shock waves around the world and left a political legacy Obama is still trying to master.
One US cable news network, MSNBC, marked the anniversary by replaying the terrifying minute-by-minute video of the first moments of the attacks when planes hit the World Trade Centre.
The Pentagon memorial is the only major official monument to the victims of the September 11 attacks, with plans for similar sites in New York and Pennsylvania held up in part by financial and legal wrangling.
In Shanksville, Pennsylvania, where United Airlines Flight 93 crashed in an open field after passengers overwhelmed the hijackers, tributes begin on Friday with a reading of victims` names.
Many believe the hijackers intended to crash the plane into the Congress building in Washington.
Prayer services and interfaith remembrances are scheduled throughout the day, with a candlelight "peace vigil" closing out the commemorations.
In a message carried on the front page of the New York Daily News, Obama declared "we are all New Yorkers" and that the attacks "will be forever seared in the consciousness of our nation."
The President wrote that his controversial and increasingly unpopular war in Afghanistan was part of his strategy "to take the fight to the extremists who attacked us on 9/11."
Washington, he said, was committed to preventing nuclear weapons proliferation and to ensuring that all "loose nuclear weapons" be accounted for and secured within four years.
People behind 9/11 plotting another attack: Mullen
Washington: Those responsible for the 9/11 terrorist attack, which killed nearly 3,000 people in the US, are still plotting and planning another attack on the United States, a top American military official said today.
"The people behind the 9/11 attacks are planning and plotting other attacks. Qaida and its extremist allies would like nothing better than to strike us again," Chairman of the Joint Chiefs of Staff Admiral Michael Mullen said at a September 11th Commemoration Ceremony at the Pentagon.
"Our grief is real and it is warranted. But we look upon this day not only with sorrow, but also with hope for the future that those we honour wanted us to have, and gratitude for the life they wanted us to live," Mullen said.