Tens of thousands of people including US government officials and relatives of the victims attend the fourth anniversary commemoration of the September 11, 2001 attacks at the former site of the World Trade Center in New York, Sept. 11, 2005.

    NEW YORK, Sept. 11 (Xinhuanet) -- Holding flowers and clutching photos of their loved ones, the siblings of those lost on Sept. 11terror attacks read out the names of the deceased Sunday morning as hundreds gathered in a solemn ceremony at Ground Zero to mark the fourth anniversary of the attacks.

    Mayor Michael Bloomberg opened the ceremony with words of condolence for those devastated by Hurricane Katrina and the terrorist bombings in the London subway.

    "Today again we are a city that meets in sadness. On this sad day our sympathy goes to our sister city of London and to Americans suffering in the aftermath of Hurricane Katrina," the mayor said.

    Shortly before 9 a.m., the brothers and sisters of the 2,749 victims began reading the names of those who perished when terrorists rammed two hijacked jet liners into the World Trade Center's twin towers.

    Relatives in the crowd bowed their heads and sobbed as speakersuttered brief, personal messages to the brothers and sisters they lost, the voices of many breaking in sorrow as they spoke directlyto their missing siblings.

    "Peter, I would give up tomorrow for one more yesterday with you," said a sister of one of the victims. "Your spirit lives in me every day, my brother," said another.

    "Kenny, your legacy of teacher, mentor, leader and coach did not die with you four years ago, but rather found new life and will live on forever," said Marie Cox, to her brother, Kenneth Phelan, a firefighter and father of four.

    At 8:46 a.m. a moment of silence was observed to commemorate the moment four years ago that American Airlines Flight 11 struck the Trade Center's north tower. Seventeen minutes later, another moment was observed to recall when United Airlines Flight 175 crashed into the south tower.

US State Secretary Condoleezza Rice delivers a speech at the fourth anniversary commemoration of the 11 September, 2001 attacks.

    Secretary of State Condoleezza Rice recited a poem by ChristinaRossetti after the second moment of silence. New York Governor George E. Pataki, former Mayor Rudolph Giuliani and New Jersey Governor Richard Codey also addressed the crowd.

    As the list was being read, family members descended to the lowest level of the site to leave flowers in a shallow pool of water for those lost. The floor of the site is considered sacred ground by those who lost loved ones in the attacks but remains virtually empty four years after the attack killed 2,749 people and tore a hole in the New York skyline.

    Families filled the water with red, orange and yellow roses, some shaking as they inscribed dedications on the wooden edge of the pool.

    Other memorials planned Sunday included a Port Authority of NewYork and New Jersey service for the 84 employees it lost on Sept. 11. Firefighters planned to roll out their trucks and other equipment in front of their firehouses.

    Parents and grandparents read the victims' names at ground zerolast year, while children's voices were heard in 2003. A selectionof politicians, relatives and others read the names on the first anniversary.

    Two light beams inspired by the twin towers were to shoot skyward Sunday night in an echo of the towers' silhouette. The "Tribute in Light" will fade away at dawn on Monday. Enditem