Musa Abu Marzuk

Iran held funeral processions on Thursday for Hamas political chief Ismail Haniyeh after he was killed in a strike in Tehran blamed on Israel.

The Islamic republic's supreme leader Ayatollah Ali Khamenei will lead the prayers for Haniyeh ahead of his burial in Doha, having earlier threatened a "harsh punishment" for his killing.

Hamas' political leader Ismail Haniyeh was killed in an Israeli strike in Iran on Wednesday, escalating tensions in the Middle East and prompted heightened global concern.

Hamas vowed the act "will not go unanswered," as its armed wing said Wednesday that the killing of its political leader takes the war with Israel to a "new levels," warning of repercussions for the entire region.