ERBIL, Kurdistan Region of Iraq – Iranian Supreme Leader Ayatollah Mojtaba Khamenei on Saturday vowed to avenge the killing of his predecessor, Ayatollah Ali Khamenei, saying those responsible for his death would face retribution.

“We pledge to avenge the pure blood of you and all the martyrs of these two wars against the criminal and disgraced killers. This revenge is the demand of our nation and must certainly be carried out,” Mojtaba Khamenei said in a statement.

On February 28, late Supreme Leader Ali Khamenei, 86, from Mashhad, was killed in a US-Israeli strike on his compound in Tehran. He served as Iran’s highest political and religious authority for nearly 37 years, making him the country's longest-serving leader since the 1979 Islamic Revolution.

Khamenei was a leading opponent of the US and Israel, advancing the Islamic Republic’s ideology by supporting regional proxies against both countries and calling for their elimination.

Following his death, Iranian officials vowed retaliation, while mourners during Khamenei’s week-long funeral processions, which began earlier this month, called for revenge and the killing of US President Donald Trump.

Trump on Saturday warned the Iranian government that “1000 missiles” are ready to strike if Tehran or its proxies act on threats to assassinate him.

“Revenge for the martyred leader of Iran is the demand of our nation and must certainly be carried out. These criminals — whose list exists from top to bottom — will take their wish for a peaceful death in bed to their graves,” the current supreme leader added.

Ayatollah Mojtaba Khamenei, who succeeded his father as supreme leader, has not made any public appearances since assuming the position. Only written statements and letters have been published under his name.

His absence has fueled speculation that he was seriously wounded in the same strike that killed his father, raising questions about his ability to effectively exercise control over the country's affairs.

Khamenei also expressed appreciation “for the tens of millions of people whose presence was awe-inspiring, enemy-defeating, and historic in the cities and villages of Iran and Iraq — particularly Tehran, Qom, Najaf, Karbala, and Mashhad.”

Millions of mourners gathered in Najaf and Karbala earlier this week for funeral ceremonies honoring the late Iranian leader after his body was brought to Iraq’s holy Shiite cities before being transferred to his final resting place in his hometown of Mashhad.

Iraq’s Iran-backed Popular Mobilization Forces (PMF) said on Thursday that more than 10 million people attended Khamenei’s funeral processions in Iraq.