Authorities are preparing for up to 3,000 potential deaths due to extreme crowds during the week-long funeral.
Around 1,000 new graves have been pre-arranged at the Behesht-e Zahra cemetery in Tehran.
Funeral processions have become stages for anti-U.S. protests and public expressions of national sentiment.
Millions are expected to attend ceremonies spanning Tehran, Qom, Karbala, and finally Mashhad on July 9.