Expert on Islamist movements Munir Adib said Thursday Jihadi elements were in charge of bombing the national security headquarters in Cairo's Shubra neighborhood. Adib added the Jihadis in Egypt had sought to avenge the security apparatus that curbed their terrorist activities in the 1990s. "The elements that carried out the bombing have only received logistical support from takfiri groups in the Sinai Peninsula," Adib added, stressing the nature and the results of the attack show lack of experience. He also indicated it was expected for Egypt to witness such attacks amid the developmental projects being constructed. Medical and security sources said a total of 29 persons were injured during the explosion that hit the national security headquarters in Shubra Al Kheima on Thursday, Egypt's Ministry of Health said. The sources added, in a statement, the explosion had not resulted in any deaths, adding that most injuries were slight.