Born near the West Bank city of Ramallah, Mashaal became the leader of Hamas' political office in 1996, directing the group from exile. Two years later, Israeli agents injected him with a slow-acting poison in Jordan, sending him into a coma before he was saved by an antidote provided by Israel as part of a diplomatic deal with Jordan.
Mashaal spent his career moving from one Arab nation to another, living in Kuwait, Jordan, Qatar and Syria. When he stepped down as head of the political office, he was succeeded in 2017 by Haniyeh. Mashaal remains an influential official in the group.
Al-Hayya, who now lives in exile in Qatar, has been a Hamas official for decades and is Sinwar's deputy. He survived an Israeli assassination attempt in 2007, when an airstrike on his home in Gaza killed members of his family while he was not there.
One of Hamas' founders, Abu Marzouk started his political career in the United Arab Emirates, where he helped found a branch of the Palestinian Muslim Brotherhood, from which Hamas was formed, according to the European Council on Foreign Relations.
He later went to the United States, where he helped found Islamic institutions, including those focused on the Palestinian cause. In 1996, when he headed Hamas' political bureau, he faced Israeli charges of financing and helping organize terrorist attacks. After 22 months spent in a New York jail on suspicion of terrorism, he agreed to relinquish his permanent resident status in the United States and said he would not contest the terrorism accusations that led to his detention. The United States then deported him to Jordan.
Deif, one of the suspected planners of the October 7, 2023, attacks, joined Hamas as a young man. In 2002, he became the leader of Hamas' military wing, the Qassam Brigades, succeeding its founder, who was killed in an Israeli strike. Deif has since orchestrated multiple attacks on Israel, including a series of suicide bombings in 1996.
In July, Israeli forces bombarded a densely packed coastal area of Gaza with heavy munitions in an attempt to kill Deif. Scores of Palestinians in Gaza were killed in the attack. Israel's military later said that it had killed Deif in the strike. Hamas has neither confirmed nor denied his death.
He had been at the top of Israel's list of most-wanted terrorists for decades, earlier evading more than eight attempts on his life, according to Israeli intelligence. In 2014, an Israeli airstrike killed one of his wives and their infant son.