Khamenei's flag-draped coffin, and those of his family killed Feb. 28 in an airstrike will be taken through the streets of Tehran on their way to Mehrabad International Airport.
Mourners wept at the sight of Khamenei's coffin alongside those of his family members also killed in the airstrike, with some chanting, "Our word is one! Revenge! Revenge!"
The dead being honored include a son-in-law, his eldest daughter, a 14-month-old granddaughter, and the wife of Iran's new Supreme Leader Ayatollah Mojtaba Khamenei.
The funeral will test Iran's battered theocracy's ability to mobilise mass public support, coming six months after a security crackdown on nationwide protests against Khamenei's rule.