The funeral procession for Iran’s slain Supreme Leader Ali Khamenei commenced in Tehran on Monday, with authorities anticipating crowds that could rival those present at his predecessor's burial nearly four decades ago. Khamenei was killed on February 28 during air strikes on his office.

After lying in state for two days at Tehran’s Grand Mosalla religious complex, Khamenei's body began its journey through the capital. The event is taking place amidst the ongoing United States-Israel war on Iran, adding a layer of political and emotional weight to the national mourning.

State broadcaster IRIB reported large numbers of mourners accompanying the procession. Authorities are reportedly aiming to prevent a recurrence of the chaos witnessed during the 1989 funeral of Ruhollah Khomeini, which saw over 10 deaths and more than 10,000 injuries due to crowd surges among an estimated 10 million attendees.

Thousands gathered on Sunday to pay their respects to Khamenei and four family members who perished with him in the February 28 air strikes. The procession on Monday is expected to last between 10 to 12 hours, with hundreds of thousands of mourners participating.

Following the Tehran procession, similar ceremonies are scheduled in the clerical center of Qom on Tuesday. The events will then extend to Iraq's holy cities of Najaf and Karbala on Wednesday. The weeklong ceremonies are set to culminate with Khamenei's burial in his birthplace, Mashhad, in northeastern Iran, on Thursday.

Images from Tehran showed vast crowds filling Revolution Square and other procession routes. Mourners were seen holding portraits of Ali Khamenei, as well as some of his son, Mojtaba Khamenei, who is being presented as a potential successor. Chants calling for revenge against the U.S. and Israel were reported among the crowds.

The scale of the funeral events underscores Khamenei's long tenure and influence within Iran. The U.S.-Israel war on Iran has already significantly reshaped the regional geopolitical landscape, and the death of Iran's highest religious and political authority marks another pivotal moment in the ongoing conflict.

Further details regarding security arrangements and the specific route of the procession have been broadcast by state media. The coming days will reveal the full impact of these ceremonies on national sentiment and the broader trajectory of the conflict.