The younger brother of Iranian President Hassan Rouhani, Hossein Fereydoun, has been arrested on financial crime charges, deputy judiciary chief of Iran Gholamhossein Mohseni Ejeie said in a televised press conference on Sunday.

“Multiple investigations have been conducted regarding this person; other people have [also] been investigated, some of whom are in jail,” Ejeie said.

“Yesterday, bail was issued for him but because he failed to secure it he was referred to prison,” Ejeie said, adding that he would be released if he secures bail, pending trial.

News of Fereydoun's arrest comes a year after the head of the General Inspection Organisation, Naser Seraj, accused him of financial violations.

Conservatives have demanded Fereydoun be put on trial, accusing of him of receiving zero-interest loans and influencing the appointment of a bank director who Rouhani had to dismiss for taking an enormous salary.

Fereydoun has acted as a key advisor and gatekeeper to Rouhani.