Iranian cyclist Bahman Golbarnezhad died Saturday at the age of 48 after suffering a cardiac arrest following a crash during the men's C4-5 road race at the Rio Paralympics 2016. The International Paralympic Committee said that the incident took place on a "mountainous stretch" of circuit.

Authorities said that Golbarnezhad received treatment at the crash site before being taken to the Unimed Rio Hospital in Barra as he suffered cardiac arrest and died "soon after arrival" at the hospital. 

An investigation is underway into the circumstances of the accident that led to the death of Golbarnezhad, who also competed at the London Paralympics in 2012.

"We're looking to gather as much information as we can and as quickly as possible - it should take a matter of days," Piers Jones, sports director of cycling's governing body Union Cycliste Internationale (UCI), reportedly said.

The Iranian flag has been lowered to half-mast in the Paralympic Village and a moment of silence will be observed during Sunday's closing ceremony. Golbarnezhad, who was the sole cyclist representing Iran, was 14th in the time-trial Wednesday.

Masoud Ashrafi, the secretary general of Iran's National Paralympic Committee, reportedly said that a request has been made for Golbarnezhad's body to be flown to 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,” said Sir Philip Craven, the International Paralympic Committee president, according to the Guardian.

Brian Cookson, UCI's president, reportedly said: "I am devastated to hear about the death of Iranian rider Bahman Golbarnezhad. Our thoughts are with his family and friends, and the NPC of Iran to whom we offer our most sincere condolences."

Carlos Nuzman, president of Rio 2016, also expressed his sorrow over Golbarnezhad's death, saying: "This is very sad news for sport and for the Paralympic movement. Our hearts and prayers are with Bahman's family, his team-mates and all the people of Iran."