Thousands of people attended the funeral of Iran’s Hamas political leader Ismail Haniyeh, who was killed in an attack in Tehran on Wednesday.
Iran’s Supreme Leader Ayatollah Ali Khamenei leads prayers before the Hamas leader is buried in Qatar.
U.S. media quoted Iranian officials as saying that the supreme leader had ordered a direct attack on Israel and that Israel was responsible for the attack on Iranian soil.
Israel has not commented directly on the assassination.
However, Prime Minister Benjamin Netanyahu said Israel had launched “devastating strikes” against its enemies in recent days, including the killing of a top Lebanese Hezbollah commander hours before the attack in Tehran.
He warned Israelis that “challenging days are ahead” as concerns about a wider conflict in the Middle East grow.
“Since the strike in Beirut, we have heard threats from all sides,” he said in a televised speech.
“We are ready for any situation and we will remain united and determined.”
United Nations Secretary-General Antonio Guterres warned of a “dangerous escalation” of hostilities in the region.
Hamas’s armed wing said the death of Haniyeh, widely seen as the group’s overall leader, would “take the fighting to new heights” and have significant consequences.
The group attacked Israel on October 7, killing approximately 1,200 people. After the attack, Israel vowed to destroy Hamas.
Haniyeh, who played a major role in ceasefire negotiations in Gaza, was killed hours after attending the inauguration of new Iranian President Masoud Pezeshkian in Tehran.
A senior Hamas official told the BBC that the killing took place in the same building where Haniyeh had stayed during a previous visit to Iran.
They said three Hamas leaders and some guards were in the same building with him.
Senior Hamas official Khalil Al-Hayya told a news conference that a missile hit Haniyeh “directly”, citing witnesses who were with him.
A senior Hamas official told the BBC that the group’s leadership was in a “state of shock”.
Hours before Haniyeh was targeted, Israel said it had killed senior Hezbollah leader Fuad Shukr in Beirut.
Israel holds him responsible for a rocket attack that killed 12 people in the Israeli-occupied Golan Heights on Saturday. Hezbollah denies any involvement.
The Iran-backed group confirmed that Shook’s body was found in the rubble of a residential building that was attacked. Four others died, including two children.