The United States marked the sixth anniversary of the September 11, 2001, terrorist attacks on the United States with ceremonies, tributes and silence all over the country. From VOA's New York Bureau, Mona Ghuneim reports.

An American flag inscribed with the names of the victims of the Sept. 11 attacks flies at the 9/11 memorial field in New York, 11 Sep 2007

Six years after the attacks that changed the Manhattan skyline forever, New Yorkers gathered Tuesday at a park near the former site of the World Trade Center to observe the anniversary.

As in years past, the New York ceremony included four moments of silence - each one in memory of the times the twin towers were hit and then fell. As in previous ceremonies, the names of more than 2,700 people who died when the towers collapsed were read out loud. Only this year, for the first time, firefighters and rescue workers who responded to the attacks and recovery efforts read the names.

"Alok Agarwal, Mukul Kumar Agarwala, and my family member - Peggy Jezycki Alario, and my partner and friend - paramedic Lieutenant Ricardo J. Quinn," read one.

New York City Mayor Michael Bloomberg speaks during a commemoration ceremony in New York, 11 Sep 2007

New York Mayor Michael Bloomberg presided over the event. Former Mayor Rudolph Giuliani also made brief remarks, despite opposition from many firefighters and victims' families who say Giuliani is using 9/11 as a way to further his presidential campaign. But the former mayor said he was chief of the city that day and has appeared at the ceremony every year.

Mayor Bloomberg said 9/11 was "the day that tore across our history and our hearts."

"We come together again as New Yorkers and as Americans to share a loss that can't be measured and to remember the names of those who can't be replaced," he said.

Family members of the victims descended to Ground Zero to lay flowers and pay their respects. Because of construction, this year's commemoration could not be held at Ground Zero itself. Family members who threatened to boycott the ceremony finally won a struggle with the city to be allowed access to the site.

Benito Colon's wife died in the South Tower that day. He paid tribute to her and read a message from their daughters.

"Time passes but the memories of you, full of love, will be our best guide," said Colon. "We love you, mommy."

President Bush, first lady Laura Bush, Vice President Dick Cheney and his wife, Lynne Cheney, take part in a moment of silence, marking the sixth anniversary of the Sept. 11 terrorist attacks, 11 Sep 2007

At the White House, President Bush and his wife observed a moment of silence. The president was joined by Vice President Dick Cheney, cabinet members and the White House staff.

Defense Secretary Robert Gates presided over a small ceremony at the Pentagon. He said that acts of terrorism will not be tolerated.

"The enemies of America, the enemies of our values and our liberty, will never again rest easy for we will hunt them down relentlessly and without reservation," said Gates.

A memorial at the Pennsylvania field where one of the hijacked planes crashed, killing the 40 passengers and crew on board, was also held.