Cairo - Security sources revealed that what is called armed people from Revolution Brigade terrorist group carried out the armed attack that targeted Egyptian security forces in Cairo's district of Nasr City that led to the killing of at least three security men late Monday. According to sources, two cells related to the extremist group carried out the attack, as they used weapons capable of penetrating explosive detection devices, in addition to Russian weapons. They added that elements from the Hasm Movement participated in the terrorist operation. The Revolution Brigade extremist group had claimed its responsibility for the terrorist operation that targeted a police training centre in Tanta previously.