Iran has sentenced Franco-Irish citizen Bernard Phelan to 6.5 years in prison for "providing information to another country", his sister said in a statement.

"The Franco-Irish citizen Bernard Phelan has just been sentenced to 6.5 years in prison in Iran for having provided information to an enemy country," Caroline Phelan said in a statement. She added that her 64-year-old brother was at risk of dying in custody.

"He had been promised an early release for health reasons before this was cancelled."

Ties between France and Iran have deteriorated in recent months with Tehran detaining seven French nationals in what Paris has said are arbitrary arrests that are equivalent to state hostage taking.

Phelan, a tourism consultant, was detained in early October as anti-government protests spread across the country.

France has demanded that Iranian authorities provide him urgent medical care due to a heart condition.

A spokesperson for Ireland's Department of Foreign Affairs said the government was extremely concerned about the case, especially given Phelan’s ill health.

Phelan's sentence comes just days after a second French national, Benjamin Briere, who has been held since May 2020 after being sentenced to eight years, was cleared of all charges and ordered to be released from prison, his lawyer said in a statement on March 2.

However, he has since remained in custody without a reason given for his ongoing detention.

In recent years, Iran's elite Revolutionary Guards have arrested dozens of dual nationals and foreigners, mostly on charges related to espionage and security.

Rights groups have accused Iran of trying to extract concessions from other countries through such arrests. Iran, which does not recognize dual nationality, denies taking prisoners to gain diplomatic leverage.

Report by Reuters