The terrorists had disguised themselves as military officers, hence they did not make the security forces suspicious, said the witness who was speaking on condition of anonymity.
He went on to say that a few minutes after the military parade began, gunshots were heard.
Initially, people thought the shootings were part of the parade, but they suddenly realized it was a terrorist attack, he said.
The terrorists caused chaos in the parade and then targeted the crowd who had gathered to watch the ceremony.
The death toll from the attack so far stands at 24, with more than 53 people wounded.
**2044
Follow us on Twitter @IrnaEnglish
Publish Date: 22 September 2018 - 17:03
Ahvaz, Sept 22, IRNA - Terrorists attacking Iran's southern city of Ahvaz opened fire at soldiers and civilians with the aim of creating fear, a witness said following the attack on Saturday.