Iraq's foreign ministry in a statement described the killing as a "flagrant violation of international law and a threat to security and stability in the region," AFP reported.
The Al-Nujaba movement, part of Resistance umbrella group in Iraq, said "the Zionists and Americans have opened the doors of hell" following the killing of Haniyeh, the targeting of a Hezbollah commander in Beirut, and a US strike on pro-Iran combatants in Iraq.
These "assassinations... will not deter us, but strengthen our determination", it added.
Hamas movement said Wednesday that Haniyeh was martyred in an Israeli strike in Iran, where he was attending the swearing-in of the newly-elected President Masoud Pezeshkian, and vowed the act "will not go unanswered."
MNA