Mohammed Diab Ibrahim al-Masri, better known as Mohammed Deif, was a Palestinian militant who served as the sixth commander of the Izz al-Din al-Qassam Brigades of Palestinian group Hamas. He succeeded Salah Shehade after the latter was killed in an Israeli airstrike in July 2002, until his own assassination by Israel in July 2024. He was succeeded by Mohammed Sinwar, the younger brother of Yahya Sinwar. He was a central figure in the Gaza war and one of the masterminds of the October 7 attacks, alongside Yahya Sinwar.