Iran’s Parliament Speaker and chief negotiator, Mohammad Bagher Ghalibaf, has called on millions of Iranians to attend the funeral of late Supreme Leader Ayatollah Ali Khamenei, urging the public to honour his legacy and send a strong message to the international community.

In a statement issued on Thursday, Ghalibaf said the funeral, scheduled to begin on Saturday, should demonstrate the nation’s resolve following Khamenei’s death in U.S.-Israeli airstrikes at the start of the recent Middle East conflict.

“I invite all the Iranian people to write a glorious page in the history of Islamic Iran through your presence,” Ghalibaf said.

“The nation’s call for vengeance must ring in the ears of the whole world,” he added.

The funeral, which was postponed during the height of the conflict, comes as Iran and the United States observe a fragile ceasefire following a preliminary agreement aimed at ending hostilities.

Khamenei, regarded as the spiritual leader of millions of Shiite Muslims, was killed at the age of 86 during strikes on his compound in central Tehran on the opening day of the war.

The main funeral ceremony will be held at Tehran’s Grand Mosalla, where his body will lie in state alongside the remains of several relatives killed during the conflict.

Iranian authorities estimate that between 15 and 20 million people could attend the funeral, potentially making it the largest state funeral in the country’s history.

To facilitate the ceremonies, public holidays have been declared in Tehran and the holy cities of Qom and Mashhad. Government offices and many private institutions in the capital will remain closed from Saturday through Monday, while traffic restrictions and airspace closures have also been announced.

After the Tehran ceremony, Khamenei’s body will be taken to the Iraqi holy cities of Najaf and Karbala before being buried on July 9 at the Imam Reza shrine in Mashhad, his birthplace in northeastern Iran.

Meanwhile, uncertainty remains over whether Khamenei’s son and successor, Mojtaba Khamenei, will make a public appearance at the funeral, having largely stayed out of public view since assuming the country’s highest leadership position.

Officials said delegations from about 30 countries are expected to attend the funeral, while thousands of mourners are also expected to travel from neighbouring Iraq, Afghanistan and Pakistan.