People participate in the commemoration ceremony in Elysian Park, Los Angeles, California, the United States on Sept. 11, 2011. Los Angeles held a ceremony in Elysian Park on Sunday to commemorate the 10th anniversary of the 9/11 terrorist attacks. [Xinhua/ Yang Lei]

 The New York ceremony began shortly after 8:30 a.m. with Mayor Michael Bloomberg who almost immediately paused for the first moment of silence to mark when the first airplane hit.

U.S. President Barack Obama read passages from the Bible and recitation of the names of the victims begun.

Music ranged from the national anthem, "The Star Spangled Banner," through other patriotic hymns to bagpipe airs, cellist Yo Yo Ma and songs including James Taylor with "Close your Eyes" and Paul Simon singing "The Sound of Silence."

Former U.S. President George W. Bush, who was president at the time of the attacks but then visiting the southern U.S. State of Florida, read a letter from former U.S. President Abraham Lincoln to the mother of five sons killed in the nation's Civil War.

Among the scores of other speakers was Rudolph Giuliani, the mayor at the time of the attacks.

In all, the nearly five-hour New York ceremonies were halted for moments of silence six times, two for the impacts of airliners, once for when each of the 110-story twin towers toppled and two additional times to mark the Pentagon and Pennsylvania crashes.

The families of victims from the 911 attacks allowed onto the site, surrounded by WTC reconstruction, headed in a steady stream to the center pieces of the memorial site set in the footprints of the two towers, sunken pools fed by surrounding waterfalls.

On dark granite stone the names of victims were engraved. With paper, crayons, pen and charcoal, family members made stone rubbings of the names.

Many cried openly, others choked back tears and sobs. Several wore T-shirts emblazoned with names and photos of victims.

At the Pentagon ceremony, U.S. Vice President Joe Biden and U.S. Defense Secretary Leon Panetta topped the list of speakers where 184 people were killed. They both vowed to relentlessly pursue al- Qaeda until it was dismantled.

Panetta noted the "incredible price" the U.S. military has paid in the wars since the 2001 attacks, 4,478 troops killed in Iraq and 1,648 on Afghanistan and more than 40,000 wounded in both conflicts.

Late in afternoon, President Obama arrived from Shanksville to lay a wreath at the Pentagon memorial.

In southeastern Pennsylvania, he also laid a wreath, but with his wife, Michele, in front of the wall of names and the thousand of people who had gathered at the crash site memorial set in a former farm field. He met with relatives of the 40 victims but did not deliver any remarks.

Many communities across the country affected 10 years ago by the attacks also held memorials this weekend.

One such was the British Commonwealth. Not far from "Ground Zero," as the WTC site was dubbed after the attacks, in Lower Manhattan, Canadian Prime Minister Stephen Harper visited the British Garden in Hanover Square. Nearly 70 British nationals died in the 9/11 attacks. More than a dozen others identified as having close ties to Britain also were victims.

More than two dozen victims of the attacks that day of infamy had close ties to the southern part of the U.S. state of California, which provided a backdrop to remembrances. One of those was Pepperdine University in Malibu, which set out 2,977 U.S. flags to honor victims.

Nearer again to New York in the U.S. State of New Jersey, across the river from Manhattan, more than 700 residents were remembered as victims.

One of them, the small northern New Jersey community of Glen Rock, with a population of a little more than 11,000 people, reeled in the loss of 11 residents to the attacks of Sept. 11, 2001.