Izz al-Din al-Qassam Brigades (IQB) – Hamas
The Izz al-Din al-Qassam Brigades (IQB) was founded in 1991 as the military wing of Hamas. It is the largest and best-equipped group operating in Gaza and has fought several wars against Israel. Since Hamas’s take-over of Gaza in 2007, the Qassam Brigades significantly enhanced their missile and rocket capacity, and has experimented with drones and underwater commandos. IQB also has its own internal security force (al-Majd).
IQB has claimed responsibility for many attacks against Israeli civilians, including suicide bombings. On 7 October 2023, over 1,000 members of Qassam brigades crossed Gaza’s border into Israel, under the cover of a heavy barrage of Hamas rocket and mortar fire, attacking Israeli military bases, towns, and a crowded music festival. They were soon joined by 5 other Palestinian armed groups, (al-Quds Brigades (Islamic Jihad), al-Aqsa Martyrs Brigades (Fatah), Abu Ali Mustafa Brigades (PFLP), Mujahideen Brigades, and the National Resistance (DFLP)).
The combined onslaught caught the Israeli military and security services unprepared and was the single biggest Israeli intelligence failure since Egypt’s surprise offensive in 1973. By the time the fighting had subsided, 1,189 people had been killed, a majority of them Israeli civilians, including 36 children. The groups also abducted at least 251 people, among them women and children.
While its centre of power remains Gaza, IQB has also maintained activities in the West Bank, including in the northern town of Jenin where it cooperates with Fatah‘s al-Aqsa Martyrs Brigades and Islamic Jihad‘s al-Quds Brigades under the umbrella of so-called ‘Jenin Battalion’.
IQB was led by Mohammed Deif and his deputy Marwan Issa — both of whom have been killed by Israel since the 7 October 2023 attacks.