Israel has reportedly denied having anything to do with the helicopter crash that killed Iranian President Ebrahim Raisi.
The two have been long-term enemies in the region in a conflict that has escalated during Israel's war against Hamas in Gaza.
Raisi, the country's foreign minister and several other officials were found dead after their helicopter crashed in a mountainous area in foggy weather on Sunday.
On Monday, an Israeli official told the Reuters news agency, "It wasn't us."
The country's supreme leader, Ayatollah Ali Khamenei, 85, who holds power in Iran, said Iran's first vice president, Mohammad Mokhber, would serve as the country's acting president until elections are held.
Khamenei had said earlier, "No disruption will occur in Iran's state affairs."
Iran recently launched a massive drone and missile attack on Israel. The attack was mostly ineffective.
The Iranian attack was launched in retaliation for an Israeli strike on the Iranian consulate in Damascus, Syria, that killed 13 people.
During Raisi's presidency, Iran enriched uranium closer than ever to weapons-grade levels, supplied bomb-carrying drones to Russia for its war in Ukraine and armed militia groups across the region, the Associated Press reported.
