Ali Khamenei
Iran's slain Supreme Leader, Ali Khamenei. Khamenei.ir / Wikimedia Commons

Thousands of mourners gathered in Tehran on Saturday as Iran began a days-long funeral for slain Supreme Leader Ayatollah Ali Khamenei, with crowds chanting 'Death to America' and 'Death to Israel' while calling for revenge over the leader's killing.

Iranian authorities expect millions to join the ceremonies, which will continue across Iran and Iraq, as the country mourns the leader who was killed in an Israeli airstrike at the start of the war earlier this year.

Khamenei died on 28 February after an Israeli strike targeted his compound at the beginning of the conflict, after nearly four decades in power. The funeral also comes as Tehran continues indirect negotiations with the United States over the future of the conflict, while tensions with Israel remain high.

Mourners Call for Revenge Against US-Israel

Authorities displayed Khamenei's casket inside a glass case at the Grand Mosalla mosque in Tehran, where thousands of mourners filed past to pay their respects. Many beat their chests in mourning, a traditional Shiite practice, while others carried portraits of the late leader, red flags symbolising revenge and banners calling for retaliation.

Chants echoed throughout the gathering, with crowds repeatedly shouting, 'Our word is one! Revenge! Revenge!' and, 'We will kill, we will kill he who killed our Imam.'

One eulogist addressed the crowd by declaring, 'We have come not for the funeral but for revenge. We're never going to give up your blood, which is the reddest line.'

Among those attending were young supporters who stated, 'We must rise up and, God willing, avenge the blood of our leader. Some became emotional while paying tribute to Khamenei.

'I am here to say goodbye to my beloved leader Ali Khamenei. I never expected to see such a day. I wish I had died before this tragedy.'

The funeral stage at the Grand Mosalla was designed to resemble the Husseiniyah, where Khamenei regularly delivered speeches before it was destroyed in the Israeli strike. Beneath his casket were those of several family members who also died in the attack. His black turban was placed atop the coffin, signifying his lineage as a descendant of the Prophet Muhammad.

Millions Expected at Khamenei's Funeral

Organisers expect attendance to reach into the millions, drawing comparisons with the funeral of Ayatollah Ruhollah Khomeini in 1989. Volunteers sprayed water over crowds and distributed cold drinks as temperatures climbed during the ceremony.

Some mourners carried portraits of Iran's new Supreme Leader, Ayatollah Mojtaba Khamenei, although he had not appeared publicly during the opening ceremony. The funeral also featured the yellow flag of Hezbollah, reflecting the presence of groups aligned with Iran's so-called 'Axis of Resistance.'

Crowds also revived familiar political slogans heard since the 1979 Islamic Revolution, including repeated chants of 'Death to America!' and 'Death to Israel!' Several attendees displayed a banner reading '#KillTrump' as US President Donald Trump marked America's 250th anniversary in South Dakota.

During his speech, Trump said, 'We knocked the hell out of Iran. They want to settle so badly. We gave them a week off for a funeral.'

Iranian authorities said Khamenei's body will travel through several cities in Iran before continuing into neighbouring Iraq as part of the funeral procession. Streets across Tehran have been closed and airspace restrictions introduced while mourning ceremonies continue.

It also remains unclear whether Mojtaba Khamenei will make a public appearance during the funeral. Israeli threats directed at the new supreme leader prompted Iran's joint military command to issue a warning earlier this week urging both Israel and the United States 'to avoid any miscalculation' during the coming days.