The brother of Iranian President Hassan Rouhani, Hossein Fereydoun, has been arrested on financial crime charges, the judiciary said on Sunday.

"Multiple investigations have been conducted regarding this person, also other people have been investigated, some of whom are in jail," deputy judiciary chief Gholamhossein Mohseni Ejeie said in a televised press conference.

"Yesterday, bail was issued for him but because he failed to secure it he was referred to prison," Ejeie said about Fereydoun, Rouhani's special aide.