In the 1980s Hebron, became the center of the Kach movement, a designated terrorist organization, whose first operations started there, and provided a model for similar behaviour in other settlements. Hebron is one of the three West Bank towns from where the majority of suicide bombers originate. In May 2003, three students of the Hebron Polytechnic University carried out three separate suicide attacks. In August 2003, in what both Islamic groups described as a retaliation, a 29-year-old preacher from Hebron, Raed Abdel-Hamed Mesk, broke a unilateral Palestinian ceasefire by killing 23 and injured over 130 in a bus bombing in Jerusalem.