Seven years after the terrorist attack on the World Trade Center, families of victims gathered at Ground Zero Thursday morning to commemorate the anniversary of the tragedy.

Like in previous years, relatives of nearly 3,000 people who perished on Sept. 11, 2001, read the names of loved ones, including those from Westchester County.

With construction at Ground Zero under way, the reading of the names was held in a park above the site. The 2,751 names were recited by family members and students from some 95 countries around the world who lost someone in the attack.

Bells tolled four times to mark the exact minutes when the two hijacked planes hit the north and south towers, and when the two smoldering towers crumbled to the ground.

Former Mayor Rudy Giuliani gave a speech at the ceremony, as he has done in previous years, along with Mayor Michael Bloomberg and Homeland Security Secretary Michael Chertoff.

"For seven years, we've come back here to be together, to feel how the entire world is linked in our circle of sorrow and mostly to remember those we loved who are never lost," Giuliani said.

Later, some families descended into the pit in order to lay flowers in a small reflecting pool, where one of the towers once stood.

The construction of new buildings and a permanent memorial to honor all those lives lost on Sept. 11 has been plagued with lengthy delays over the past seven years. On the eve of the anniversary, Mayor Bloomberg set a deadline for the 10th anniversary, three years away, for the unveiling of a permanent memorial at the site.

In the meantime, the void in the Manhattan skyline will be filled by two blue beams of light, which will once again pierce the darkness in honor of the fallen towers.

To see the entire Sept. 11 Ground Zero ceremony, go to iO Extra, Channel 612 on your iO digital cable box.Click here for a recap of Sept.11, 2001