Senior Hamas leader Ismail Haniyeh was reportedly killed in Iran, adding to the list of Hamas leaders who have been targeted for assassination. The group has swiftly replaced those who have been killed, despite its opaque leadership structure. Among Hamas's prominent leaders are Yahya Sinwar, the head of Hamas in Gaza, who is believed to be hiding in the group's tunnel network, and is seen as more radical than Haniyeh. Khaled Meshal, former political head of Hamas, continues to be influential in the organization. Mohammed Deif, the commander of Hamas's military, has orchestrated multiple attacks on Israel and his fate remains unclear. Other key leaders include Khalil al-Hayya, Mousa Abu Marzouk, and Marwan Issa, who was killed in an Israeli strike in March. The death of Haniyeh is predicted to make a ceasefire more difficult to achieve.