TEHRAN (AFP) — Iran held a funeral ceremony 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 Agence France-Presse correspondent.

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, as crowds chanted “Death to Israel, Death to America!”

Iran’s Revolutionary Guards announced Haniyeh’s death the day before. They said he and a bodyguard were killed in a strike on their accommodation in the Iranian capital at 2 a.m. 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, raising fears of a wider regional conflict as the Israel-Hamas war in Gaza continues unabated.

Israel has declined to comment on the Tehran strike.

Iran’s state TV showed the coffins of Haniyeh and his bodyguard covered in Palestinian flags during the ceremony attended by senior Iranian officials including President Masoud Pezeshkian and Islamic Revolutionary Guard Corps chief, General Hossein Salami.

Haniyeh had been visiting Tehran for Pezeshkian’s inauguration ceremony on Tuesday.

Khalil al-Hayya, Hamas’ foreign relations chief, vowed during the funeral ceremony that Haniyeh’s message will live on and “we will pursue Israel until it is uprooted from the land of Palestine.”