The names of 12 students and a teacher who were killed in the Columbine High School shooting have been read out at a ceremony marking 20 years since the massacre.

White doves were released, ending three days of gatherings to remember those who died on 20 April 1999, when Eric Harris and Dylan Klebold, aged 18 and 17, attacked the Colorado school.

They exchanged fire with police officers at the scene before shooting and killing themselves.

Image: Eric Harris and Dylan Klebold killed 13 people

They had planted explosives inside and left the building and waited, but went back in when they failed to detonate and began their killing spree.

More than 2,000 people attended the memorial event in a park near the high school on Saturday.


Image: Hundreds of people laid flowers

Dawn Anna's 18-year-old daughter Lauren Townsend was killed in the library.

At the memorial, Ms Anna said: "We're changed. We're weaker in some places, but hopefully we're stronger in most of them. Our hearts have giant holes in them. But our hearts are bigger than they were 20 years ago."

Patrick Ireland was shot three times but managed to escape.

Image: The massacre took place 20 years ago

He was captured on camera dangling from a second-storey window before falling into the arms of SWAT officers.

He had to learn to walk and talk again.

"Our innocence was stolen," he said.

"How can that ever be repaid? But forgiveness is a process. It takes time. It takes practice, repetition, translating that rhythm into moving."

Image: Columbine survivor Patrick Ireland spoke at the memorial

Frank DeAngelis, who was the school's head teacher at the time, said he begins every morning by reciting the names of those who died.

Mr DeAngelis read the 13 names aloud to end the memorial.

A bell rang 13 times, and white doves soared into the sky for each victim.

Visitors left cards and flowers at the memorial site which sits atop a hill overlooking the school.

Image: Former Columbine High School head teacher Frank DeAngelis read the victims' names

The concrete wall contains several plaques, some featuring quotes from officials and Columbine students and teachers, the others with the names of the teacher and 12 students who were killed.

Ahead of the various memorial events, the FBI announced they were hunting a teenager "infatuated" with the 1999 Columbine massacre, who had travelled to Colorado on Monday night from Miami and bought weapons from a store in the area.

Image: Will Beck, a Columbine High School massacre survivor, attended

Sol Pais, 18, was later found dead at the bottom of Mount Evans, southwest of Denver, at the Echo Lake Lodge, with a self-inflicted gunshot wound.

Image: Sol Pais is said to have bought a pump-action shotgun. Pic: @FBIDenver

Authorities said she had made violent threats to schools in Denver ahead of the 20th anniversary of the attack.

The victims were Cassie Bernall, 17, Steven Curnow, 14, Corey DePooter, 17, Kelly Fleming, 16, Matthew Kechter, 16, Daniel Mauser, 15, Daniel Rohrbough, 15, Rachel Scott, 17, Isaiah Shoels, 18, John Tomlin, 16, Lauren Townsend, 18, Kyle Velasquez 18 and teacher William 'Dave' Sanders, 47.