Foreign Minister Hakan Fidan will attend a funeral for Ismail Haniyeh, the head of Hamas' political bureau, who was assassinated by Israel in Tehran, a Turkish diplomatic source said Thursday.

Fidan was to fly to Qatar's capital Doha late Thursday to attend the funeral that will be held on Friday, the source told Reuters.

Haniyeh was killed with his bodyguard in a predawn strike on their accommodation in the Iranian capital early Wednesday, fueling fears of a wider regional conflict.

Haniyeh was in the Iranian capital for the inauguration of President Masoud Pezeshkian. The killing has sent shockwaves around the world and prompted major protests in the region, including in Türkiye.

A plane carrying his body landed in Doha Thursday after a public funeral procession in Iran attended by crowds of mourners who paid their respects, Qatar-based network Al Jazeera reported.

Haniyeh was Hamas's lead negotiator in efforts for a truce and hostage release deal for Gaza, where Israel has killed more than 39,000 Palestinians, mostly women and children, since Oct. 7.

Fidan on Wednesday said Israel killed the prospects of peace by assassinating Haniyeh, criticizing U.S. support for Israel’s crimes.

Türkiye will observe a national day of mourning on Friday, President Recep Tayyip Erdoğan said.

The strike on Haniyeh is widely assumed to have been carried out by Israel, but Prime Minister Benjamin Netanyahu's government made no claim of responsibility and said it would make no comment on the killing.