The assassination of Hamas political leader Ismail Haniyeh in Tehran has dealt a major blow to cease-fire negotiations to end the war in Gaza, as well as a release deal for the Israeli hostages held by Hamas. The attack — along with the killing of a senior Hezbollah official in Beirut — has also heightened fears of a wider Middle East conflict, as Iran vowed to avenge Haniyeh’s death. Haniyeh was the chief negotiator for the Palestinian militant group in cease-fire talks. Funerals for Haniyeh and senior Hezbollah commander Fuad Shukr will be held Thursday in Tehran and Beirut, respectively.