A massive outpouring of mourning was witnessed in Tehran as the funeral ceremonies for the late Iranian supreme leader, Ayatollah Ali Khamenei, commenced on Saturday. His body is lying in state at the Grand Mosalla in Tehran and will remain there until Monday before embarking on a journey across Iran and Iraq. The Iranian authorities anticipate an attendance of 15-20 million people over the next few days, marking one of the largest funeral gatherings as a proportion of the country's population. Khamenei was killed in US and Israeli strikes in late February, which escalated into a regional conflict. The ceremonies are expected to culminate with his burial at the Imam Reza Shrine in Mashhad next Thursday. In Tehran, central areas will be locked down as masses of supporters of the Islamic regime chant slogans against the US and call for revenge for Khamenei's death. The funeral procession will include stops in Qom, Najaf, Karbala, and other significant religious sites, with ceremonies continuing across Iran for 40 days following his burial. Ayatollah Khamenei was succeeded as Iran's supreme leader by his son, Mojtaba, who has not appeared publicly since assuming the role, sparking speculation about his health and raising questions about his potential appearance at the funeral.