U.S. President Barack Obama and first lady Michelle Obama will mark the 10th anniversary of the September 11, 2001, terrorist attacks by visiting the sites that were struck in New York, at the Pentagon outside Washington, and in Pennsylvania.

Spokesman Jay Carney said the president will pay tribute to those who lost their lives, as well as honor those who responded to the disaster on a day that is etched in the minds of Americans. Mr. Obama also plans to honor military personnel who have served in the country's subsequent wars in Iraq and Afghanistan, as well as other missions aimed at rooting out the terrorists responsible for the attacks.

On the eve of the anniversary, Vice President Joe Biden is to attend the dedication of a memorial in Shanksville, the rural community in Pennsylvania where a jetliner crashed as passengers and crew fought the hijackers who had commandeered the aircraft.

New York Mayor Michael Bloomberg has said former president George W. Bush, who was in office at the time of the attacks, will join Mr. Obama at the commemoration in New York. Most of those killed on September 11, 2001, were inside the two towering World Trade Center buildings that collapsed after terrorists flew passenger jets into their upper floors.

Bloomberg said dignitaries gathered for the 10th anniversary will not give speeches, but rather read poems or quotes appropriate for the occasion.

The New York ceremony will also mark the opening of a memorial plaza, where the names of the nearly 3,000 people killed in the September 11 attacks, as well as those killed in a 1993 attack on the World Trade Center, have been etched into bronze panels.