A security guard and three members of the Muslim Brotherhood (MB) terrorist group were killed Saturday, in Damietta city, following clashes between the MB and security forces, Al Youm7 news reported. The security forces imposed strict measures for search and arrest operations. Meanwhile, unidentified assailants blocked the Damietta-Dakahlia road and set fire to a public service bus Saturday morning. The MB released a statement threatening to escalate violence, after 13 girls affiliated to the terrorist group were held in custody over Tuesday's clashes, which left a soldier dead and 30 others injured.