OKLAHOMA CITY (AP) — Church bells rang out again Thursday in Oklahoma City as families and friends marked the sixth anniversary of the bombing of the Alfred P. Murrah Federal Building.

On the memorial marking the spot, dedicated one year ago, speakers read the names of the 149 adults and 19 children killed in the April 19, 1995, blast.

"As we have for the past six years, we come together today to honor and respect those who were so senselessly taken from us, those who have persevered so much pain and those who worked so selflessly to help on that terrible morning," said Bob Johnson, chairman of the Oklahoma City National Memorial Foundation.

"Your loved ones have not been forgotten and the memorial is a fitting tribute to assure that they never will be," he told listeners.

The families stood silent for 168 seconds, ending with the ringing of church bells and the song "Let There Be Peace on Earth."

Ted Wilson, an Oklahoma City Fire Department chaplain, prayed that those considering acts of terror could "see through the eyes of those present here today, of those who are not here, of those who can never be here."

Edye Stowe lost two sons in the bombing — Chase, who would be 8, and Colton, who would be 10. "It's hard that they'd be old enough to play baseball now," Stowe said. "I just want to get on with my life."

Kari Watkins, spokeswoman for the memorial, said families and bombing survivors "just wanted to have a low-key, simple ceremony."

"Other years we've had a groundbreaking or been under construction," she said. "Now, things are done."

Hundreds of people, including President Clinton, attended the fifth anniversary ceremony, when the memorial on the bombing site opened. Two months ago, President Bush dedicated a museum on the memorial grounds.

The memorial includes 168 empty chairs; the "Survivor Tree," an elm tree that lived through the bombing though badly damaged; a reflecting pool; and bronze gates that symbolically preserve the moment of the explosion, 9:02 a.m.

Timothy McVeigh, convicted in the bombing, is scheduled to be executed May 16 at the federal prison in Terre Haute, Ind.