NEW YORK, Sept 11 (Reuters) Americans observed a moment of silence at the very hour and place of the first September 11 attack today, the sixth anniversary of a day remembered with solemnity and ceremony.
Speaking near Ground Zero, where the twin World Trade Center towers were destroyed by hijacked planes on September 11, 2001, Mayor Michael Bloomberg told families of those who died: ''Six years have passed and our place is still by your side.'' Rain fell on the somber ceremony as some wore funereal black to remember the 2,750 people killed when the towers were destroyed one after the other. Their names were due to be read out loud over four hours.
Similar ceremonies were taking place in Washington, where the Pentagon was attacked by a third plane, and Shanksville, Pennsylvania, where a fourth plane crashed after passengers fought with al Qaeda hijackers that day.
Bagpipes played, accompanied by a steady drum beat, in a New York city park neighboring the former disaster site which is now a busy construction zone.
The first of four New York moments of silence -- followed by the ringing of church bells -- took place at 1816 hrs the hour the first plane struck. Other moments were set for when the second plane struck and when each tower fell.
September 11 fell on a Tuesday again for the first time since 2001, yet another reminder of the day.
While Americans mourned, al Qaeda released another video today, following one last week in which Osama bin Laden called on Americans to embrace Islam to avert war.
The new, 47-minute video featured only a still picture of bin Laden -- no moving video -- while he eulogizes one of the 19 hijackers, Waleed al-Shehri, as a rare and magnificent man.
The new video also shows Shehri delivering his last testament in which he chastises Americans and welcomes death.
The term 9/11 uses the American convention of enumerating the month before the date. In all, 2,993 people died, including the 19 hijackers.
LIKE PEARL HARBOR ''It's the kind of event that will not really fade emotionally until everyone who was alive at the time has died,'' said Larry Sabato, director of the Center for Politics at the University of Virginia.
''It takes a while. It was really the 1960s before you could discuss Pearl Harbor rationally without using epithets for the Japanese,'' he said of Japan's attack on the US base in Hawaii on December 7, 1941.
Nor can 9/11 be separated from politics, especially with former New York Mayor Rudy Giuliani running for president. He leads most of the national polls for the Republican nomination, largely on the strength of his performance that day.
Some groups representing the families of victims opposed giving Giuliani a speaking role in the commemoration, raising concerns he would use the platform to promote his presidential aspirations. But Giuliani will speak as planned, and his aides have insisted that he will not politicize the event.
New York television station WABC tried to deviate from the past by not broadcasting the reading of the names of the dead but backtracked in the face of stiff public opposition.
Bloomberg himself tried to move this year's commemoration entirely off site because Ground Zero is under construction.
Families of the victims protested and Bloomberg relented, allowing them limited access.
''It inhibited political speech,'' said Doug Muzzio, public affairs professor at New York's Baruch College. ''That's beginning to diminish but as long as there's a war on terror and there's a politics of terror, 9/11 is going to be a symbol of it.
''Without doubt it will persist through this election cycle,'' he said in a reference to the November 2008 presidential election.
REUTERS SBC BST2119