U.S. Vice President Joe Biden spoke of a special fraternity and New York Mayor Michael Bloomberg of selfless acts as New York City commemorated the eighth anniversary of the attacks on the World Trade Center Friday morning.

The ceremony, chaired by Mayor Bloomberg, is being held at Ground Zero, where the twin towers stood, to remember those who died in the coordinated attacks on Sept. 11, 2001.

Bloomberg requested all those attending to stand in silence to pay tribute to the victims in the terror attacks eight years ago.

Flute and cello players played somber tunes while survivors of the victims stood in drizzle falling from a black sky, reading the names of their loved ones. Some still burst into tears despite the eight years that have passed since the tragedy.

As many as 2,752 people were killed on Sept. 11, 2001.

President Barack Obama wrote a special message for the day, which called the terrorist attacks on Sept. 11, 2001 "a tragedy that will be forever seared in the consciousness of our nation."

"No one can guarantee that there will never be another attack," Obama said, "but what I can guarantee - what I can promise - is that we will do everything within our power to reduce the likelihood of an attack, and that I will not hesitate to do what it takes to defend America."

Obama signed into law a measure this year that designated Sept. 11 as a National Day of Service.

Vice President Joe Biden, Secretary of Homeland Security Janet Napolitano, Senator Charles Schumer, former Mayor Rudolph W. Giuliani, who played a significant role in the rescue work after 9/11 attacks, and other senior government officials attended the ceremony.

Biden joined families who were laying flowers in a reflecting pool on the site where the two towers once stood and then he told the hundreds of victims' relatives gathered that "there's a special fraternity for those of us who've lost spouses and children."

While extending his condolences to those who were killed while working in the Twin Towers, Bloomberg said the day should also be remembered for the many who volunteered to help in the aftermath of the attack, including the 343 firefighters who died when rescuing people in the Twin Towers.

"Their compassion and selfless acts are etched in our city's history," Bloomberg said.

"From this day forward, we will safeguard the memories of those who died by rekindling the spirit of service that lit our city with hope and helped keep us strong," he said.

As the names of all the victims were read out, a new name was added for the second time in the past eight years.

Leon Heyward died of lung disease and cancer last year, and it was recognized that his death was caused by breathing toxic dust when the Twin Towers collapsed. He spent hours in rescuing his colleagues in a nearby government building.

(Xinhua News Agency September 12, 2009)