Mohammed Deif

Mohammed Deif was commander-in-chief of Hamas’s military wing, the Izz ad-Din al-Qassam Brigades, from 2002 until his death in 2024, and the single figure most responsible for turning Hamas from a street movement into an organized force capable of mass-casualty attacks on Israeli civilians, culminating in the October 7, 2023 massacre. For three decades he was Israel’s most wanted man in Gaza, surviving at least seven assassination attempts before an airstrike finally killed him in July 2024, a fact Hamas itself would not admit for more than six months.

Who he was

Born Mohammed Diab Ibrahim al-Masri on 12 August 1965 in the Khan Younis refugee camp in the southern Gaza Strip, he studied science at Gaza’s Islamic University. He took the nom de guerre “Deif,” Arabic for “guest,” a reference to the itinerant, hidden existence he adopted once he became a marked man: he moved constantly, rarely slept in the same place twice, and appeared in public so rarely that no confirmed photograph of him circulated from after the 1990s.

What he built

Deif joined Hamas within weeks of its founding by Sheikh Ahmed Yassin in December 1987, entering the group’s nascent military wing under the 1988 covenant that committed it to Israel’s destruction. His mentor was Yehya Ayyash, the bombmaker known as “the Engineer”; after Israel killed Ayyash in a 1996 booby-trapped phone, Deif inherited both his methods and his mission. Israeli intelligence credits him as chief architect of Hamas’s 1994 to 1996 wave of suicide bombings on Israeli buses and city streets, attacks that killed dozens of civilians in Tel Aviv, Jerusalem, Ashkelon and Netanya, which Hamas framed publicly as retaliation for Baruch Goldstein’s 1994 Hebron massacre even though the bombing campaign had already begun before Goldstein acted. Palestinian Authority security services arrested Deif in May 2000 under Israeli pressure; he escaped Palestinian custody that December with the help of sympathetic guards and was never recaptured.

He became commander of the Qassam Brigades in 2002, after Israel killed his predecessor Salah Shehade, and over the next two decades built the Brigades from scattered cells into an organized force with a rocket arsenal, an extensive tunnel network under Gaza, and a chain of command that survived repeated attempts to decapitate it. He directed rocket fire and soldier-abduction operations through the Second Intifada and each of the Gaza wars that followed, and Israel held him personally responsible for the 2006 capture of soldier Gilad Shalit.

The hunt

Israel tried to kill Deif at least seven times over three decades. The closest near-miss came in August 2014, during that summer’s Gaza war, when an airstrike on a house in Khan Younis killed his wife Widad and two of his children; Deif survived, badly wounded. Israel targeted him again twice during the May 2021 fighting; he escaped both strikes. His survival, strike after strike, made him a legend inside Hamas and a standing embarrassment to Israeli intelligence, and by the 2020s he was widely regarded as untouchable.

October 7 and the end

Deif was, alongside Yahya Sinwar and deputy commander Marwan Issa, one of the chief architects of the October 7, 2023 attack, the assault that killed roughly 1,200 people in Israel in a single day and included the mass abduction of hostages and documented sexual violence that United Nations investigators later confirmed had occurred. On the morning of the attack, Deif recorded an audio message announcing what Hamas called “Operation al-Aqsa Flood,” framing the massacre as a response to Israeli actions at the Temple Mount and in the West Bank; he did not mention, and never has, that the operation had been planned for roughly two years and required no Israeli provocation on the day itself. As the Qassam Brigades’ top commander, Deif retained overall command of Hamas’s forces through the opening phase of the war that followed.

On 13 July 2024, an Israeli airstrike hit a compound in the al-Mawasi area of Khan Younis, killing Khan Younis Brigade commander Rafah Salama; Deif was in the same room. Israel spent two weeks assessing the strike before announcing on 1 August 2024 that intelligence had confirmed his death “to a complete certainty.” Hamas denied the killing for months, reportedly because it had lost contact with him and his remains were badly disfigured; Arabic-language reporting in November 2024 said Hamas’s own security officials had privately concluded he was dead after testing partial remains, and Hamas issued a formal public confirmation only in early 2025.

Myths and the record

Hamas’s own account casts Deif as a folk hero, the “ghost commander” who eluded the Israeli military for thirty years, and his death was mourned across Gaza as martyrdom. That framing omits what he did with those thirty years: he built and ran the operational machinery, bus bombings in the 1990s, rocket barrages in the 2000s, the October 7 massacre in 2023, that killed and abducted Israeli civilians as a matter of strategy, not incidental casualty. A second, smaller myth ran the other way for a time: Hamas’s months-long refusal to confirm his death fed speculation that Israel had exaggerated or fabricated the strike’s success. Hamas’s own eventual admission settled that question in Israel’s favor.

Yahya Sinwar · October 7 attacks · Hamas · Who attacked first on October 7 · Who attacked first, every war · The Laws of War