Iran has postponed a planned public mourning ceremony for Supreme Leader Ayatollah Ali Khamenei in Tehran, days after he was killed alongside several family members in joint US-Israeli air strikes.

State-affiliated Tasnim news agency reported that the delay was due to logistical challenges, including requests from people across multiple provinces who wish to attend. Analysts meanwhile stated security risks were also a consideration.

The ceremony had initially been scheduled to begin at 10pm local time at Tehran’s Imam Khomeini Prayer Hall and to continue over three days. Hojjatoleslam Mahmoudi, head of Iran’s Islamic Propagation Council, had earlier urged citizens to attend in large numbers to pay their respects.

Security concerns are however looming over the event. With millions expected to mourn, authorities face the risk of potential further attacks amid escalating hostilities between Iran, Israel and the United States.

When Ayatollah Ruhollah Khomeini, founder of the Islamic Republic, died in 1989, an estimated 10 million people attended his funeral.

Khamenei, 86, had served as Iran’s supreme leader since 1989, succeeding Khomeini after the 1979 revolution. As supreme leader, he held ultimate authority over the armed forces, judiciary and key state institutions, while serving as the country’s highest religious authority.

Attention has now shifted to the question of succession. Ayatollah Ahmad Khatami, a senior cleric and member of both the Guardian Council and the Assembly of Experts, said the process of selecting a new leader is nearing completion but acknowledged that the country remains in a “war situation.”

Under Iran’s constitution, the 88-member Assembly of Experts is responsible for appointing the supreme leader by simple majority vote. Candidates must be senior Islamic jurists with strong political judgment, administrative capability and religious credentials. Among those widely considered a leading contender is Khamenei’s second son, Mojtaba Khamenei.

Meanwhile, Israel’s Defence Minister warned that any successor who continues policies hostile to Israel would face the threat of assassination.

In a statement posted online on Wednesday, he said any future Iranian leader pursuing the destruction of Israel or threatening the United States and regional allies would be considered a target.

US President Donald Trump also commented publicly on Iran’s future leadership, saying the “worst-case scenario” would be another figure opposed to US interests.

Regional analysts say Iran’s political system has long prepared for the possibility of Khamenei’s death, with institutional structures designed to ensure continuity of command during crises.

Even so, the coming days are expected to be pivotal, as the country navigates both mass public mourning and a high-stakes transition of power under the shadow of war.

NATO on Wednesday strongly condemned Iran’s targeting of Türkiye and reiterated its firm commitment to defending all member states amid escalating regional tensions.

A NATO spokesperson said the alliance “stands firmly with all Allies, including Türkiye,” as Iran continues strikes across the region.

“Our deterrence and defense posture remains strong across all domains, including air and missile defense,” the spokesperson added, underscoring the alliance’s readiness to respond to threats.

Earlier, Türkiye’s Defense Ministry reported that a ballistic projectile launched from Iran toward Turkish airspace was intercepted and destroyed by NATO air and missile defense units operating in the Eastern Mediterranean.

According to the ministry, the munition was tracked after transiting Iraqi and Syrian airspace before being successfully neutralized.

The incident marks a further escalation in regional hostilities and highlights NATO’s heightened alert posture along its southeastern flank.

At least 80 people were killed after a US submarine torpedoed and sank an Iranian Navy warship in the Indian Ocean near Sri Lanka, according to a report by Reuters.

The United States has not confirmed the reported death toll. However, US Defence Secretary Pete Hegseth acknowledged the strike, describing it as a demonstration of America’s global military reach amid its ongoing war with Iran.

“An American submarine sunk an Iranian warship that thought it was safe in international waters. Instead, it was sunk by a torpedo,” Hegseth told reporters.

Sri Lankan authorities said 32 crew members were rescued from the frigate IRIS Dena following the attack. A further 148 sailors remain missing, with search efforts ongoing and hopes fading that additional survivors will be found.

Hegseth referred to the strike as a “quiet death,” calling it the first time since World War II that the United States has sunk an enemy vessel using a torpedo. “Like in that war,” he said, “we are fighting to win.”

The Pentagon has said one of the central objectives of the US-Israeli military campaign against Iran, launched over the weekend, is to dismantle Iran’s naval capabilities.

The sinking marks a significant escalation in maritime hostilities, expanding the conflict further into the Indian Ocean and raising concerns about regional shipping routes and broader security implications.