Iran held funeral processions on Thursday with calls for revenge after the killing in Tehran of Hamas political chief Ismail Haniyeh in a strike blamed on Israel.

The Islamic republic’s supreme leader Ayatollah Ali Khamenei led prayers for Haniyeh ahead of his burial in Qatar, having earlier threatened a “harsh punishment” for his killing.

In Tehran’s city center, thousands of mourning crowds carrying posters of Haniyeh and Palestinian flags gathered for the ceremony at Tehran University before a procession, according to an AFP correspondent.

Haniyeh’s death was announced the day before by Iran’s Revolutionary Guards, who said he and his bodyguard were killed in a strike on their accommodation in the Iranian capital at 2:00 a.m. (2230 GMT) on Wednesday.

It came just hours after Israel targeted and killed top Hezbollah commander Fuad Shukr in a retaliatory strike on the Lebanese capital Beirut, sending fears of a wider regional war soaring in fallout from the Israel-Hamas war in Gaza.

Israel has declined to comment on the Tehran strike.

Iran’s state TV showed the coffins of Haniyeh and his bodyguards covered in Palestinian flags during the ceremony attended by senior Iranian officials.

President Masoud Pezeshkian and Islamic Revolutionary Guard Corps chief, General Hossein Salami, were present. Haniyeh had been visiting Tehran for Pezeshkian’s inauguration ceremony on Tuesday.

Senior Hamas figure Khalil Al-Hayya, the movement’s foreign relations chief, vowed during the funeral ceremony that “Ismail Haniyeh’s slogan, ‘We will not recognize Israel,’ will remain an immortal slogan” and “we will pursue Israel until it is uprooted from the land of Palestine.”

Iran’s conservative parliamentary speaker Mohammad Bagher Ghalibaf said Iran “will certainly carry out the supreme leader’s order (to avenge Haniyeh.)”

“It is our duty to respond at the right time and in the right place,” he said in a speech with crowds chanting “Death to Israel, Death to America!”

The caskets, with a black-and-white pattern resembling a Palestinian keffiyeh scarf, were borne on a flower-bedecked truck through leafy streets where cooling water mists sprayed the flag-waving crowds.

Khamenei, who has the final say in Iran’s political affairs, said after Haniyeh’s death that it was “our duty to seek revenge for his blood as he was martyred in the territory of the Islamic Republic of Iran.”

The Islamic republic has not yet officially published any information on the exact location of the strike.