Presidential candidates John McCain and Barack Obama were to pay silent respects at ground zero Thursday afternoon and later attend a city forum on public service. McCain also was scheduled to attend a memorial service in Shanksville, Pa., for the 40 people killed aboard United Airlines Flight 93.
Family members and students representing more than 90 countries that lost citizens on Sept. 11, 2001, were to read the names of the more than 2,700 people killed in New York.
Some mourners wondered if the remembrance would, or should, continue as it has indefinitely. About 3,500 people attended last year's ceremony, a roughly 25 percent decrease from 2006.
"We've kept it alive, and perhaps kept it alive too long," said Charles Wolf, whose wife, Katherine, was killed at the World Trade Center. "How many times do you reopen the wounds?"
Wolf, who lives in downtown Manhattan, attends the ceremony every year but said it has become more painful, especially to stand in silence for the moment that the plane crashed into the tower where his wife worked. "It's one thing to remember," he said, "but it's another to relive it."
Other victims' relatives worry that Sept. 11 will revert to being just another date on the calendar.
"The remembrances have to continue; for how long, I can't say," said Barbara Minervino of Middletown, N.J., whose husband, Louis, died in the twin towers. "But we have to memorialize the fact that this day happened in the history of the United States and the history of the world. The day we forget, then why are we living?"
Minervino planned to attend a noon Mass in her husband's memory after listening to the names being read during the memorial service in New York.
That service moved to a park just east of ground zero last year because of construction at the trade center site. But family members are allowed to descend seven stories below ground and touch the spot where their loved ones died.
The ceremony was to include the reading of 2,751 victims' names, one more than last year. The city restored Sneha Philip, a woman who vanished on Sept. 10, to its official death toll this year after a court ruled that she was likely killed at the trade center.
Former Mayor Rudy Giuliani was scheduled to speak at the ceremony, as he has every year, along with officials including Mayor Michael Bloomberg and Homeland Security Secretary Michael Chertoff.
Last year's reading by Giuliani, then a Republican presidential candidate, drew protests from family members who said the city was ill-prepared for the terrorist attacks under his leadership and questioned whether he should be there while running for the White House. They had no opposition to McCain and Obama' visit this year.
In Arlington, Va., Defense Secretary Robert Gates was scheduled to speak at a ceremony dedicating the memorial at the Pentagon, the first of three major Sept. 11 memorials to be completed.
The 2-acre park, located at the spot where American Airlines Flight 77 crashed into the Pentagon's west wall, consists primarily of 184 cantilevered benches, each bearing a victim's name.
President Bush and first lady Laura Bush were to mark the anniversary during a moment of silence on the South Lawn of the White House. The president was then to head to the Pentagon memorial.
In Pennsylvania, bells were to toll and victims' names were being read in a reclaimed minefield in Shanksville where Flight 93 came down after passengers reportedly stormed the cockpit to thwart terrorists' plans to use that plane as a weapon like the others.
Memorials are years away from being built in Pennsylvania and New York. The stalled, complex rebuilding of office towers, a transit station and memorial at ground zero led New York Gov. David Paterson to order a reevaluation of budgets and schedules for all projects. The Lower Manhattan Development Corp., the agency that owns the site, has said the planned 8-acre memorial might not completed by the 10th anniversary of the attacks.
Associated Press writers Matthew Barakat in Arlington, Va., Ramit Plushnick-Masti in Shanksville, Pa., Wayne Parry in Atlantic City, N.J., and Tom Hays in New York contributed to this report.