1. ITV Report

Columbine remembers shooting victims on 20th anniversary of massacre

Students supports one another at the scene of the 1999 Columbine shooting.

Twenty years on from one of the US' worst shootings, a community is reflecting on those lost.

On the morning of April 20, 1999 two gunmen opened fire on their classmates at Columbine High School in Littleton, Colorado.

Dylan Klebold, 17, and Eric Harris, 18 had planned the attack for weeks. As part of their preparations for the pre-meditated murder, they filmed themselves in woodland using bowling pins as target practice.

Their victims included 12 of their classmates and one teacher. A further 21 people were injured.

The pair later took their own lives in the school's library before they could be apprehended by authorities.

Students were pictured fleeing the school during the 1999 massacre.

The school shooting was not the country's first, and certainly not its last. But what is most is shocking is Columbine played a role in inspiring future massacres.

When 20 primary school children were killed at Sandy Hook in 2012, it was proven the gunman had been motivated by the events 11 years earlier in Colorado.

The link between Columbine and the Parkland shooting is less clear, but both imprint the reality of shooting in America's classrooms as a depressing feature of the nation's education system.

The mother of seven-year-old Josephine, killed at Sandy Hook, now campaigns for gun safety in classrooms. Credit: ITV News

Josephine was just seven-years-old when she lost her life at Sandy Hook.

Her mother, Michelle Gay, has devoted her life to ensuring such a tragic atrocity cannot happen again. She believes preparing children as young as pre-school age is essential and sees gun drills as "life skills for today's world."

Two decades on from Columbine, a great deal remains unchanged.

Students have galvanised behind an anti-gun movement, mourning their classmates as they protest. But the US' powerful gun lobbyists insist more guns mean greater safety.

Until that changes, the safety of the classrooms in one of the world's most developed nations remains at risk.