Almost three decades on, Iran has laid 175 military divers to rest. They were captured during the 1980 to 1988 war with Iraq.
Dug up from the Iraqi side of the river border, Tehran’s military claims the divers were buried alive.
Pictures in Iranian media last month showed the bodies dressed in diving gear and hands crudely tied with wire.
Emotional crowds packed the capital’s streets to commemorate the divers and other soldiers killed during the war.
Speaking from Tehran, euronews reporter Javad Montazeri said: “These bodies are from a battle between two countries who were at war many years ago. Two countries who have a good relationship today, and who are fighting together against a single enemy (referring to ISIL).”
Those locked in today’s battle against the self-proclaimed Islamic State are praised for protecting Shi’ite sites in Iraq.
“We have great respect for those who are killed defending holy shrines. We are going to be there, fighting until our last breath,” said one man in Tehran.
Another added: “It is my duty to defend the borders of my country. Like all those who are gone, and they were much younger than me. They’ve given us a big lesson in honour.”
The divers laid to rest were taken prisoner in 1986, during an Iranian attempt to seize Basra. Iraq repelled the attack and thousands were killed on both sides.
The public gathering, commemorating a war that continues to shape Iranian politics, followed a more intimate ceremony on Monday evening, where mourners read passages from the Koran and laid flowers on the divers’ coffins.