Hundreds of people gathered at the site of the Oklahoma City bombing Tuesday to honor and remember victims of the attack 16 years ago.
The bombing of the Murrah Federal Building on April 19, 1995 killed 168 men, women and children.
The attack was the country's first experience with terrorism on such a large scale, and remains the worst act of domestic terror on U.S. soil.
President Barack Obama sent his condolences to the families affected by the tragedy, and stressed America's commitment to combatting terrorism.
"We also need to remember the resilience and toughness of the American people and know that our nation's resolve to fight terror and combat violent extremism, in all its forms, will not waver," he said.
"As a nation we should take a moment to recognize the courage and spirit of our fellow citizens, the first responders who rushed to the site to save countless lives, and the people of the nation who stood together to lift up this tight-knit community," Obama added.
A bagpipe procession began at 8:45 a.m. Tuesday at the National Memorial Museum in Oklahoma City. Those who gathered observed a 168-second
moment of silence, starting at 9:02 a.m., the time of the bombing.
"The memorial is a testament to the sacrifices of those killed and injured in the bombing, as well as the rescue workers who worked tirelessly to pull survivors from the rubble," said Oklahoma Gov. Mary Fallin, who was the state's lieutenant governor at the time of the bombing.
"The memorial is a reminder of so many people who stepped forward to help 16 years ago," she added.
About 300 survivors attended the ceremony. Relatives read the names of the victims.
Bomber Timothy McVeigh was convicted on federal murder and conspiracy charges in 1997 and executed in 2001.