Bells tolled throughout New York City and mourners observed a moment of silence to mark the time terrorists began their attack on the US nine years ago.
Politics threatened to overshadow today’s day of mourning for nearly 3,000 September 11 victims amid a polarising national debate over a mosque planned blocks from the World Trade Centre site.
The first plane hijacked by Islamic extremists hit the centre’s north tower at 8:46am in 2001. Within hours, both towers were rubble and thousands were dead there, at the Pentagon and at a crash site in Shanksville, Pennsylvania.
Thousands of protesters for and against the planned Islamic centre are expected to hold rival demonstrations after the typically sombre anniversary ceremony.
Bagpipes and drums played to open the ceremony, followed by brief comments by Mayor Michael Bloomberg.
“Once again we meet to commemorate the day we have come to call 9/11. We have returned to this sacred site to join our hearts together, the names of those we loved and lost,” Mr Bloomberg said.
“No other public tragedy has cut our city so deeply. No other place is as filled with our compassion, our love and our solidarity.”
A moment of silence began at 8:46am (1.46pm Irish time), the time the first hijacked jetliner hit the north tower of the World Trade Centre in 2001.
President Barack Obama and first lady Michelle Obama were attending separate services at the Pentagon in Washington and a rural field in Shanksville, Pennsylvania.
But the rallies planned in New York embroiled victims’ family members in a feud over whether to play politics on the ninth anniversary of the attacks.
Nancy Nee, whose firefighter brother was killed at the World Trade Centre, is bitterly opposed to the Park51 proposed mosque and Islamic community centre near ground zero. But she didn’t plan to join other family members at an anti-mosque rally hours after the anniversary ceremony.
“I just wanted to be as at peace with everything that’s going on as I possibly can,” Ms Nee said.
Even nine years later, she said, her brother George Cain’s death “is still very raw. ... And I just don’t have it in me to be protesting and arguing, with anger in my heart and in my head.”
Jim Riches planned to pay respects at ground zero to his firefighter son, Jimmy, then attend the rally.
“My son can’t speak anymore. He’s been murdered by Muslims. I intend to voice my opinion against the location of this mosque,” Mr Riches said. “If someone wants to go home, that’s their right. I have the right to go there.”
The heated mosque debate – pitting advocates of religious freedom against critics who say putting an Islamic centre so close to ground zero disrespects the dead – led Mr Obama to remind Americans on Friday, “We are not at war against Islam.”
In his Saturday radio address, he alluded to the contentious atmosphere.
“This is a time of difficulty for our country,” he said. “And it is often in such moments that some try to stoke bitterness – to divide us based on our differences, to blind us to what we have in common.
But he added, “we do not allow ourselves to be defined by fear, but by the hopes we have for our families, for our nation, and for a brighter future”.
A threat to burn copies of the Muslim holy book on the anniversary – which had set off international protests – was apparently called off. The Florida pastor who made the threat flew to New York on Friday night and appeared on NBC’s Today show.
He said his church would not burn the Koran, a plan that inflamed much of the Muslim world and drew a stern rebuke from Obama.
“We feel that God is telling us to stop,” he told NBC. Pressed on whether his church would ever burn the Islamic holy book, he said: “Not today, not ever. We’re not going to go back and do it. It is totally cancelled.”
Jones said his Gainesville, Florida, church’s goal was “to expose that there is an element of Islam that is very dangerous and very radical.”
“We have definitely accomplished that mission,” he said.
He said that he flew to New York in the hopes of meeting with leaders of the Islamic centre but that no such meeting was scheduled.
Imam Feisal Abdul Rauf, leader of the planned mosque, said that he was “prepared to consider meeting with anyone who is seriously committed to pursuing peace” but had no meeting planned with Mr Jones.
In Afghanistan, shops and police checkpoints were set on fire as thousands of people protested against Mr Jones’ plan and chanted “Death to America” in Logar province. At least 11 people were injured on Friday in similar protests in Badakhshan province.
In Indonesia, the world’s most populous Muslim country, cleric Rusli Hasbi told 1,000 worshippers at Friday prayers that whether or not Mr Jones burns the Koran, he already has “hurt the heart of the Muslim world”.
Activists in New York insisted their intentions were peaceful. More than 1,000 protesters on both sides of the issue were expected to converge at the mosque site, a former clothing factory two blocks north of the trade centre site.
“It’s a rally of remembrance for tens of thousands who lost loved ones that day,” said Pamela Geller, a conservative blogger and host of the anti-mosque demonstration. “It’s not a political event, it’s a human rights event.”
Four red, white and blue balloons rose early today from a public telephone booth near the building. Police cars lined the blocked-off street in front of the building.
Rosario Piedrahita, arriving with a bouquet of flowers and a photograph of her nephew, victim Wilder Alfredo Gomez, said she opposed using the site for a mosque.
“I say it’s not good,” she said. “It’s like people standing up to celebrate after a victory.”
John Bolton, who was US ambassador to the United Nations under President George W. Bush, was expected to send a videotaped message of support to the anti-mosque rally, as was conservative blogger Andrew Breitbart.
Anti-Islam Dutch politician Geert Wilders, who advocates banning the Koran and taxing Muslim women who wear head scarves, planned to address the crowd in person, along with a handful of Republican congressional candidates who have made opposition to the mosque a centrepiece of their campaigns.
Muslim prayer services are normally held at the site, but it was padlocked on Friday and would be closed Saturday, the official end of the holy month of Ramadan. Police planned 24-hour patrols of the site until next week. Worshippers on Friday were redirected to a different prayer room 10 blocks away.
While the president was at the Pentagon service and the first lady was to join former first lady Laura Bush at Shanksville, Vice President Joe Biden planned to speak at the New York ceremony, where 2,752 people were killed when two jetliners flew into the trade centre.