World Trade Centre Attacks: 20 Years Since First Attack On New York Towers (PICTURES)

PICTURES: 20 Years Since World Trade Centre Bombing

More than 1,000 people were injured and six killed in the first attack on the World Trade Centre, which rocked the United States 20 years ago on Tuesday.

A ceremony is set to take place in New York honouring those who died. It will be held at the 9/11 memorial at the site where the Twin Towers were hit eight years later, killing more than 2,700 people.

Six Islamist terrorists were convicted of the 1993 bombing from a truck parked in an underground garage below the north tower.

To mark the anniversary, here are some of the most striking images from that tragic day.