The Iranian parliament on Wednesday blocked the appointment of a politician from the Sunni minority as vice president, state media reported.
In August, President Masoud Pezeshkian had announced the appointment of Abdolkarim Hosseinzadeh as his vice president for rural development and disadvantaged areas, citing his "valuable experience".
But on Wednesday lawmakers voted against his resignation from parliament to take up the vice president post, the official IRNA news agency said.
"Parliament members voted 107 in favour, 129 against, and five abstentions out of the 247 representatives present," it added.
Sunni Muslims account for around 10 percent of Iran's population, where the vast majority are Shiites and that branch of Islam is the official state religion. They have very rarely held key positions of power since the Islamic revolution in 1979.
Iran has numerous vice presidents, who are tasked with leading organisations related to presidential affairs in the country.
A 44-year-old reformist, Hosseinzadeh has since 2012 represented the northwestern cities of Naghadeh and Oshnavieh in the Iranian parliament.
He has spoken out publicly on several occasions in defence of the rights of Iran's Sunnis.
During his election campaign Pezeshkian, himself a reformist, criticised the lack of representation for ethnic and religious minorities, in particular Sunni Kurds, in important positions.