The 31st International Islamic Unity Conference started here on Tuesday with a speech delivered by President Hassan Rouhani.
The event which is being held with the attendance of 500 foreign and domestic participants continues until Dec 7.
The Unity Requirements of Modern Islamic Civilization is the main theme of the conference.
Prominent international and domestic figures are to address the event
The participants are scheduled to be received by the Supreme Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei on Wednesday.
The conference guests also paid homage on Monday to the founder of the Islamic Republic, the late Imam Khomeini at his mausoleum in southern Tehran and laid wreath on his grave.