And as prayers were said for those injured in another school shooting in Georgia last week, President Bill Clinton urged the House of Representatives to vote quickly on new gun restrictions approved by the Senate last week.

Rob Watson reports: "Despite the shooting the graduation ceremony went ahead as planned"

After crying at funerals and memorials since the shooting, the 437 Columbine seniors did their best to make graduation a happy memory.

They smiled as they marched down the aisle to their seats watched by family and friends.

One student seeks comfort

But there was also overwhelming sadness at the killings carried out by Eric Harris, 18, and Dylan Klebold, 17. The pair turned their guns on themselves after carrying out the massacre.

Two of the those killed would have graduated at the ceremony. Harris and Klebold were also set to graduate, but their names were not mentioned.

"Two of the graduating seniors of the Class of 1999 and one of our faculty members are no longer with us. Their lives were cut down too short," Principal Frank DeAngelis said, referring to the two seniors and teacher and coach Dave Sanders.

Silent tribute

"Their lives were full of courage and hope and enthusiasm and never forget that they loved us as much as we loved them," he said.

"Each of us will carry the spirit of Isaiah Shoels, Lauren Townsend and Dave Sanders into the future."

People then bowed their head in a moment of silence to remember the victims.

Ms Townsend, 18, had planned to attend Colorado State University and study wildlife biology.

Her sister and two brothers accepted her diploma and her parents were handed her cap and gown and valedictorian award.

Wounded victims

Graduate Sara Martin, remembered her friend Cassie Bernall.

"I wish that I had had more time and more opportunities to tell her what she meant to me," she said. "I must recognise what I have learned - to love deeply and to appreciate every word and every gesture of every person I love or will love."

The audience cheered when three seniors who had been wounded in the massacre, Jeanna Park, Lisa Kreutz and Valeen Schnurr, received their diplomas.