The Iranian National Paralympic Committee have confirmed para-cyclist Bahman Golbarnezhad has died after a crash in Rio.
Golbarnezhad was involved in an accident on the first section of the Grumari loop on Saturday, a mountainous stretch of the course.
The 48-year-old received emergency treatment at the scene of his accident and was in the process of being taken to hospital when he suffered a cardiac arrest.
However, he did not recover from his injuries and died soon after arrival at the Unimed Rio Hospital in Barra.
"Regretfully, I.R.IRAN NPC announces that Bahman Golbarnezhad, passed away because of his accident during the competition," a statement from the Iranian National Paralympic Committee read.
Philip Craven, International Paralympic Committee (IPC) president, added: "This is truly heart-breaking news and the thoughts and condolences of the whole Paralympic Movement are with Bahman's family, friends, and teammates as well as the whole of the National Paralympic Committee (NPC) of Iran.
"The Paralympic Family is united in grief at this horrendous tragedy which casts a shadow over what have been great Paralympic Games here in Rio."
The IPC confirmed an investigation into the circumstances of the accident has been launched.